Catalyst and adsorption compositions having adhesion characteristics

ABSTRACT

A composition and method for improving the adhesion properties of catalytic and adsorptive compositions to a substrate through the addition of clay and/or silicone binder is disclosed. Preferably, the composition includes manganese dioxide and attapulgite clay and/or a silicone polymer which is adhered to a metal substrate, such as a motor vehicle radiator.

RELATED APPLICATION

This is a C-I-P of Ser. No. 08/682,174 filed Jul. 16, 1996, which is aC-I-P application of U.S. Ser. No. 08/589,182 filed Jan. 19, 1996, nowabandoned, which is a C-I-P of U.S. Ser. No. 08/537,206 filed Sept. 29,1995, now abandoned, which is a C-I-P of U.S. Ser. No. 08/410,445 filedMar. 24, 1995, now abandoned, which is a C-I-P of U.S. Ser. No.08/376,332 filed Jan. 20, 1995, now abandoned, all of said applicationsare herein incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an apparatus for cleaning theatmosphere; and more particularly to a vehicle comprising at least oneatmosphere contacting surface having a pollution treating compositionthereon, and a related method and composition.

2. Discussion of the Related Art

A review of literature relating to pollution control reveals that thegeneral approach is to reactively clean waste streams entering theenvironment. If too much of one pollutant or another is detected orbeing discharged, the tendency has been to focus on the source of thepollutant, the cause of the pollutant or the waste stream containing thepollutant. For the most part gaseous streams are treated to reduce thepollutants prior to entering the atmosphere.

It has been disclosed to treat atmospheric air directed into a confinedspace to remove undesirable components in the air. However, there hasbeen little effort to treat pollutants which are already in theenvironment; the environment has been left to its own self cleansingsystems. References are known which disclose proactively cleaning theenvironment. U.S. Pat. No. 3,738,088 discloses an air filtering assemblyfor cleaning pollution from the ambient air by utilizing a vehicle as amobile cleaning device. A variety of elements are disclosed to be usedin combination with a vehicle to clean the ambient air as the vehicle isdriven through the environment. In particular, there is disclosedducting to control air stream velocity and direct the air to variousfilter means. The filter means can include filters and electronicprecipitators. Catalyzed postfilters are disclosed to be useful to treatnonparticulate or aerosol pollution such as carbon monoxide, unburnedhydrocarbons, nitrous oxide and/or sulfur oxides, and the like. GermanPatent DE 43 18 738 C1 also discloses a process for the physical andchemical cleaning of outside air. Motor vehicles are used as carriers ofconventional filters and/or catalysts, which do not constituteoperational components of the vehicle but are used to directly cleanatmospheric air.

Another approach is disclosed in U.S. Pat. No. 5,147,429. There isdisclosed a mobile airborne air cleaning station. In particular thispatent features a dirigible for collecting air. The dirigible has aplurality of different types of air cleaning devices contained therein.The air cleaning devices disclosed include wet scrubbers, filtrationmachines, and cyclonic spray scrubbers.

The difficulty with the above recited devices disclosed to proactivelyclean the atmospheric air is that they require new and additionalequipment. Even the modified vehicle disclosed in U.S. Pat. No.3,738,088 requires ducting and filters which can include catalyticfilters.

DE 40 07 965 C2 to Klaus Hager discloses a catalyst comprising copperoxides for converting ozone and a mixture of copper oxides and manganeseoxides for converting carbon monoxide. The catalyst can be applied as acoating to a self heating radiator, oil coolers or charged-air coolers.The catalyst coating comprises heat resistant binders which are also gaspermeable. It is indicated that the copper oxides and manganese oxidesare widely used in gas mask filters and have the disadvantage of beingpoisoned by water vapor. However, the heating of the surfaces of theautomobile during operation evaporates the water. In this way,continuous use of the catalyst is possible since no drying agent isnecessary.

Manganese oxides are known to catalyze the oxidation of ozone to formoxygen. Many commercially available types of manganese compound andcompositions, including alpha manganese oxide are disclosed to catalyzethe reaction of ozone to form oxygen. In particular, it is known to usethe cryptomelane form of alpha manganese oxide to catalyze the reactionof ozone to form oxygen.

Alpha manganese oxides are disclosed in references such as O'Young,Hydrothermal Synthesis of Manganese Oxides with Tunnel Structures,Modern Analytical Techniques for Analysis of Petroleum, presented at theSymposium on Advances in Zeolites and Pillared Clay Structures beforethe Division of Petroleum Chemistry, Inc. American Chemical Society NewYork City Meeting, Aug. 25-30, 1991 beginning at page 348. Suchmaterials are also disclosed in U.S. Pat. No. 5,340,562 to O'Young, etal. Additionally, forms of α-MnO₂ are disclosed in McKenzie, theSynthesis of Birnessite, Cryptomelane, and Some Other Oxides andHydroxides of Manganese, Mineralogical Magazine, December 1971, Vol. 38,pp. 493-502. For the purposes of the present invention, α-MnO₂ isdefined to include hollandite (BaMn₈O₁₆.xH₂O), cryptomelane(KMn₈O₁₆.xH₂O), manjiroite (NaMn8O₁₆.xH₂O) and coronadite(PbMn₈O₁₆.xH₂O). O'Young discloses these materials to have a threedimensional framework tunnel structure (U.S. Pat. No. 5,340,562 andO'Young Hydrothermal Synthesis of Manganese Oxides with TunnelStructures both hereby incorporated by reference). For the purposes ofthe present invention, α-MnO₂ is considered to have a 2×2 tunnelstructure and to include hollandite, cryptomelane, manjiroite andcoronadite.

SUMMARY OF THE INVENTION

The present invention relates to an apparatus, method and composition totreat the atmosphere. For the purposes of the present inventionatmosphere is defined as the mass of air surrounding the earth.

The present invention is directed to an apparatus and related method fortreating the atmosphere comprising a vehicle and a means such as a motorto translate the vehicle from one place to another through theatmosphere. The vehicle comprises at least one atmosphere contactingvehicle surface and a pollutant treating composition located on thatsurface. The atmosphere contacting surface is a surface of a componentof the vehicle that is in direct contact with the atmosphere. Preferredand useful atmosphere contacting surfaces include body surfaces, winddeflector surfaces, grill surfaces, mirror backs and the surfaces of“under the hood” components. Preferred atmosphere contacting surfacesare located within the body of the motor vehicle, typically in proximityto the engine, i.e., the engine compartment. The surfaces are preferablythe surfaces of cooling means which comprise an in flow path for liquidsor gases through a coolant walled enclosure such as tubes or a housingand an outer surface on which is located fins to enhance heat transfer.Preferred atmosphere contacting surfaces comprise a finned outer surfaceand are selected from the outer surfaces of the radiator, airconditioner condenser, the surfaces of the radiator fan, engine oilcooler, transmission oil cooler, power steering fluid cooler and aircharge cooler also referred to as an intercooler or after cooler. Themost preferred atmosphere contacting surfaces are the outer surfaces ofthe air conditioner condenser and radiator due to their large surfacearea and relatively high ambient operating temperatures of from about40° C. to 135° C. and typically up to 110° C.

An advantage of the present invention is that the atmosphere contactingsurface useful to support a pollution treating composition can be thesurface of existing vehicle components. No additional filter, orapparatus to support a pollutant treating composition, is required.Accordingly, the apparatus and method of the present invention can belocated on existing components of new cars or retrofitted onto old cars.Retrofitting may comprise coating a suitable pollutant treatingcomposition on an existing vehicle surface which comes in contact withatmospheric air as the vehicle is driven through the atmosphere.

The present invention is directed to compositions, methods and articlesto treat pollutants in air. Such pollutants may typically comprise from0 to 400 parts, more typically 1 to 300, and yet more typically 1 to200, parts per billion (ppb) ozone; 0 to 30 parts, and more typically 1to 20, parts per million (ppm) carbon monoxide; and 2 to 3000 ppbunsaturated hydrocarbon compounds such as C₂ to about C₂₀ olefins andpartially oxygenated hydrocarbons such as alcohols, aldehydes, esters,ethers, ketones and the like. Typical hydrocarbons which can be treatedinclude, but are not limited to, propylene, butylene, formaldehyde andother airborne hydrocarbon gases and vapors. Other pollutants presentmay include nitrogen oxides and sulfur oxides. The National Ambient AirQuality Standard for ozone is 120 ppb, and for carbon monoxide is 9 ppm.

Pollutant treating compositions include catalyst compositions useful forcatalyzing the conversion of pollutants present in the atmosphere tonon-objectionable materials. Alternatively, adsorption compositions canbe used as the pollutant treating composition to adsorb pollutants whichcan be destroyed upon adsorption, or stored for further treatment at alater time.

Catalyst compositions can be used which can assist in the conversion ofthe pollutants to harmless compounds or to less harmful compounds.Useful and preferred catalyst compositions include compositions whichcatalyze the reaction of ozone to form oxygen, catalyze the reaction ofcarbon monoxide to form carbon dioxide, and/or catalyze the reaction ofhydrocarbons to form water and carbon dioxide. Specific and preferredcatalysts to catalyze the reaction of hydrocarbons are useful forcatalyzing the reaction of low molecular weight unsaturated hydrocarbonshaving from two to twenty carbons and at least one double bond, such asC₂ to about C₈ mono-olefins. Such low molecular weight hydrocarbons havebeen identified as being sufficiently reactive to cause smog. Particularolefins which can be reacted include propylene and butylene. A usefuland preferred catalyst can catalyze the reactions of both ozone andcarbon monoxide; and preferably ozone, carbon monoxide and hydrocarbons.

Ozone—Useful and preferred catalyst compositions to treat ozone includea composition comprising manganese compounds including oxides such asMn₂O₃ and MnO₂ with a preferred composition comprising α-MnO₂, andcryptomelane being most preferred. Other useful and preferredcompositions include a mixture of MnO₂ and CuO. Specific and preferredcompositions comprise hopcalite which contains CuO and MnO₂ and, morepreferably CARULITE® catalyst which contains MnO₂, CuO and Al₂O₃ andsold by the Carus Chemical Co. An alternative composition comprises arefractory metal oxide support on which is dispersed a catalyticallyeffective amount of a palladium component and preferably also includes amanganese component. Also useful is a catalyst comprising a preciousmetal component, preferably a platinum component on a support ofcoprecipitated zirconia and manganese oxide. The use of thiscoprecipitated support has been found to be particularly effective toenable a platinum component to be used to treat ozone. Yet anothercomposition which can result in the conversion of ozone to oxygencomprises carbon, and palladium or platinum supported on carbon,manganese dioxide, CARULITE® catalyst and/or hopcalite. Manganesesupported on a refractory oxide such as alumina has also been found tobe useful.

Carbon Monoxide—Useful and preferred catalyst compositions to treatcarbon monoxide include a composition comprising a refractory metaloxide support on which is dispersed a catalytically effective amount ofa platinum and/or palladium component, preferably a platinum component.A most preferred catalyst composition to treat carbon monoxide comprisesa reduced platinum group component supported on a refractory metaloxide, preferably titania. Useful catalytic materials include preciousmetal components including platinum group components which include themetals and their compounds. Such metals can be selected from platinum,palladium, rhodium and ruthenium, gold and/or silver components.Platinum will also result in the catalytic reaction of ozone. Alsouseful is a catalyst comprising a precious metal component, preferably aplatinum component on a support of coprecipitated zirconia and manganesedioxide. Preferably, this catalyst embodiment is reduced. Other usefulcompositions which can convert carbon monoxide to carbon dioxide includea platinum component supported on carbon or a support comprisingmanganese dioxide. Preferred catalysts to treat such pollutants arereduced. Another composition useful to treat carbon monoxide comprises aplatinum group metal component, preferably a platinum component, arefractory oxide support, preferably alumina and titania and at leastone metal component selected from a tungsten component and rheniumcomponent, preferably in the metal oxide form.

Hydrocarbons—Useful and preferred catalyst compositions to treatunsaturated hydrocarbons including C₂ to about C₂₀ olefins and typicallyC₂ to C₈ mono-olefins such as propylene and partially oxygenatedhydrocarbons as recited have been found to be the same type as recitedfor use in catalyzing the reaction of carbon monoxide with the preferredcompositions for unsaturated hydrocarbons comprising a reduced platinumand/or palladium component and a refractory metal oxide support for theplatinum component. A preferred refractory metal oxide support istitania. Other useful compositions which can convert hydrocarbons tocarbon dioxide and water include a platinum component supported oncarbon or a support comprising manganese dioxide. Preferred catalysts totreat such pollutants are reduced. Another composition useful to converthydrocarbons comprises a platinum group metal component, preferably aplatinum component, a refractory oxide support, preferably alumina andtitania and at least one metal component selected from a tungstencomponent and rhenium component, preferably in the metal oxide form. Acombination of a platinum component and a palladium component results inimproved CO conversion at an increase in cost and is most preferredwhere greater conversion is desired and cost increase is acceptable.

Ozone and Carbon Monoxide—A useful and preferred catalyst which cantreat both ozone and carbon monoxide comprises a support such as arefractory metal oxide support on which is dispersed a precious metalcomponent. The refractory oxide support can comprise a support componentselected from the group consisting of ceria, alumina, silica, titania,zirconia, and mixtures thereof. Also useful as a support for preciousmetal catalyst components is a coprecipitate of zirconia and manganeseoxides. Most preferably, this support is used with a platinum componentand the catalyst is in reduced form. This single catalyst has been foundto effectively treat both ozone and carbon monoxide. Other useful andpreferred precious metal components are comprised of precious metalcomponents selected from palladium and also platinum components withpalladium preferred. A combination of a ceria support with a palladiumcomponent results in an effective catalyst for treating both ozone andcarbon monoxide. Other useful and preferred catalysts to treat bothozone and carbon monoxide include a platinum group component, preferablya platinum component and/or palladium component and more preferably aplatinum component, on titania or on a combination of zirconia andsilica. A combination of a platinum component and a palladium componentresults in improved CO conversion at an increase in cost and is mostpreferred where greater conversion is desired and cost increase isacceptable. Other useful compositions which can convert ozone to oxygenand carbon monoxide to carbon dioxide include a platinum componentsupported on carbon or on a support comprising manganese dioxide.Preferred catalysts are reduced.

Ozone, Carbon Monoxide and Hydrocarbons—A useful and preferred catalystwhich can treat ozone, carbon monoxide and hydrocarbons, typically lowmolecular weight olefins (C₂ to about C₂₀) and typically C₂ to C₈mono-olefins and partially oxygenated hydrocarbons as recited comprisesa support, preferably a refractory metal oxide support on which isdispersed a precious metal component. The refractory metal oxide supportcan comprise a support component selected from the group consisting ofceria, alumina, titania, zirconia and mixtures thereof with titania mostpreferred. Useful and preferred precious metal components are comprisedof precious metal components selected from platinum group componentsincluding palladium and/or platinum components with platinum mostpreferred. It has been found that a combination of a titania supportwith a platinum component results in the most effective catalyst fortreating ozone, carbon monoxide and low molecular weight gaseous olefincompounds. A combination of a platinum component and a palladiumcomponent results in improved CO and hydrocarbon conversion at anincrease in cost and is most preferred where greater conversion isdesired and cost increase is acceptable. It is preferred to reduce theplatinum group components with a suitable reducing agent. Other usefulcompositions which can convert ozone to oxygen, carbon monoxide tocarbon dioxide, and hydrocarbons to carbon dioxide include a platinumcomponent supported on carbon, a support comprising manganese dioxide,or a support comprising a coprecipitate of manganese oxides andzirconia. Preferred catalysts are reduced.

The above compositions can be applied by coating to at least oneatmosphere contacting vehicle surface. Particularly preferredcompositions catalyze the destruction of ozone, carbon monoxide and/orunsaturated low molecular weight olefinic compounds at ambientconditions or ambient operating conditions. Ambient conditions are theconditions of the atmosphere. By ambient operating conditions it ismeant the conditions, such as temperature, of the atmosphere contactingsurface during normal operation of the vehicle without the use ofadditional energy directed to heating the pollutant treatingcomposition. Certain atmosphere contacting surfaces such as a grill orwind deflector can be at the same or similar temperature as theatmosphere. It has been found that preferred catalysts which catalyzethe reaction of ozone can catalyze the reaction of ozone at ambientconditions in ranges as low as 50° C. to 30° C.

Atmosphere contacting surfaces may have higher temperatures than theambient atmospheric temperatures due to the nature of the operation ofthe component underlying the surface. For example, preferred atmospherecontacting surfaces are the surfaces of the air conditioning condenserand the radiator due to their high surface area. Where vehicles use aircharge coolers, these are preferred due to high surface area andoperating temperatures of from ambient to 250° F. Normally, duringambient operating conditions the surfaces of these components increaseto higher temperature levels than the ambient environment due to thenature of their operation. After the vehicle motor has warmed up, thesecomponents are typically at temperatures which range up to about 130° C.and typically from 40° C. to 110° C. The temperature range of theseatmosphere contacting surfaces helps to enhance the conversion rates ofthe ozone, carbon monoxide and hydrocarbon catalysts supported on suchsurfaces. Air charge coolers operate at temperatures up to about 130° C.and typically from 60° C. to 130° C.

Various of the catalyst compositions can be combined, and a combinedcoating applied to the atmosphere contacting surface. Alternatively,different surfaces or different parts of the same surface can be coatedwith different catalyst compositions.

The method and apparatus of the present invention are designed so thatthe pollutants can be treated at ambient atmospheric conditions or atthe ambient operating conditions of the vehicle atmosphere contactingsurface. The present invention is particularly useful for treating ozoneby coating motor vehicle atmosphere contacting surfaces with suitablecatalysts useful to destroy such pollutants even at ambient conditions,and at vehicle surface temperatures typically from at least 0° C.,preferably from 10° C. to 105° C., and more preferably from 40° C. to100° C. Carbon monoxide is preferably treated at atmosphere contactingsurface temperatures from 40° C. to 105° C. Low molecular weighthydrocarbons, typically unsaturated hydrocarbons having at least oneunsaturated bond, such as C₂ to about C₂₀ olefins and typically C₂ to C₈mono-olefins, are preferably treated at atmosphere contacting surfacetemperatures of from 40° C. to 105° C. The percent conversion of ozone,carbon monoxide and/or hydrocarbons depends on the temperature and spacevelocity of the atmospheric air relative to the atmosphere contactingsurface, and the temperature of the atmosphere contacting surface.

Accordingly, the present invention, in most preferred embodiments canresult in at least reducing the ozone, carbon monoxide and/orhydrocarbon levels present in the atmosphere without the addition of anymechanical features or energy source to existing vehicles, particularlymotor vehicles. Additionally, the catalytic reaction takes place at thenormal ambient operating conditions experienced by the surfaces of thesemotor vehicle elements so that no changes in the construction or methodof operation of the motor vehicle are required.

While the apparatus and method of the present invention are generallydirected to treating the atmosphere, it will be appreciated thatvariations of the apparatus are contemplated for use to treat volumes ofair in enclosed spaces. For example, a motor vehicle having anatmosphere contacting surface supporting a pollutant treatingcomposition can be used to treat the air within factories, mines andtunnels. Such apparatus can include vehicles used in such environments.

While the preferred embodiments of the present invention are directed tothe destruction of pollutants at the ambient operating temperatures ofthe atmosphere contacting surface, it is also desirable to treatpollutants which have a catalyzed reaction temperature higher than theambient temperature or ambient operating temperature of the atmospherecontacting surface. Such pollutants include hydrocarbons and nitrogenoxides and any carbon monoxide which bypasses or is not treated at theatmosphere contacting surface. These pollutants can be treated at highertemperatures typically in the range of at least 100° C. to 450° C. Thiscan be accomplished, for example, by the use of an auxiliary heatedcatalyzed surface. By an auxiliary heated surface, it is meant thatthere are supplemental means to heat the surface. A preferred auxiliaryheated surface is the surface of an electrically heated catalyzedmonolith such as an electrically heated catalyzed metal honeycomb of thetype known to those skilled in the art. Electricity can be provided bybatteries or a generator such as are present in motor vehicles. Thecatalyst composition can be any well known oxidation and/or reductioncatalyst, preferably a three way catalyst (TWC) comprising preciousgroup metals such as platinum, palladium, rhodium and the like supportedon refractory oxide supports. An auxiliary heated catalyzed surface canbe used in combination with, and preferably downstream of, the vehicleatmosphere contacting surface to further treat the pollutants.

As previously stated, adsorption compositions can also be used to adsorbpollutants such as hydrocarbons and/or particulate matter for lateroxidation or subsequent removal. Useful and preferred adsorptioncompositions include zeolites, other molecular sieves, carbon, and GroupIIA alkaline earth metal oxides such as calcium oxide. Hydrocarbons andparticulate matter can be adsorbed from 0° C. to 110° C. andsubsequently treated by desorption followed by catalytic reaction orincineration.

It is preferred to coat areas of the vehicle that have a relatively highsurface area exposed to a large flow rate of atmospheric air as themotor vehicle is driven through the environment. For land use motorvehicles, particularly preferred atmosphere contacting surfaces includethe radiator, fan blades, the air conditioning condenser or heatexchanger, air charge cooler, engine oil cooler, transmission oilcooler, and wind deflectors of the type used on the roof of truck cabs.

Most preferably, the atmosphere contacting surface is a surface of aradiator. The radiator has a large surface area for enhanced cooling ofinternal combustion engine fluid coolants. By applying a catalyst to besupported on the radiator surface, advantage can be taken of the largehoneycomb-like surface area, usually with little or no effect on thecooling function of the radiator. The high honeycomb-like surface areaenables a maximization of contact of the catalyst with the air passingthrough the honeycomb-like design of the radiator. Additionally,radiators in many automobiles are located behind the air conditionercondenser and are thereby protected by the air conditioner condenser.

The present invention includes methods to coat pollutant treatingcompositions on to atmosphere contacting surfaces of motor vehicles. Inparticular, the present invention includes a method to coat catalystcompositions onto finned elements such as radiators, air conditionercondensers, and air charge coolers.

Calculations suggest that in motor vehicle traffic congested areas,there are a sufficient number of motor vehicles to significantly impactpollutants treated in accordance with the present invention. Forexample, in Southern California's South Coast Air Quality ManagementDistrict, there are approximately eight million cars. It has beencalculated that if each car travels 20 miles per day, all of the air inthis region to an altitude of 100 feet can be cycled through radiatorsin one week.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side schematic view of a truck showing a grill, airconditioner condenser, electrically heated catalyst, air charge cooler,radiator, fan and engine with a wind deflector on the roof of the truckcab.

FIG. 2 is a partial schematic view of a motor vehicle showing the grill,air conditioner condenser, radiator and fan.

FIG. 3 is a front view of the radiator.

FIG. 4 is a front view of the air conditioner condenser.

FIG. 5 is a front view of a wind deflector of the type illustrated inFIG. 1.

FIG. 6 is a front view of the truck of FIG. 1.

FIG. 7 is a partial schematic sectional view of coated finned coolingelement.

FIG. 8 is a photograph of the coated radiator from Examples 1 and 2.

FIGS. 9-14 and 16-17 are graphs of CO conversion versus temperature forusing different catalysts in Examples 4, 9-12, 14 and 15.

FIG. 15 is a graph of propylene conversion versus temperature based onExample 14.

FIG. 18 is a graph of ozone conversion versus temperature based onExample 17.

FIG. 19 is an IR spectrum for cryptomelane.

FIG. 20 is an XRD pattern for cryptomelane shown as counts using asquare root scale versus the Bragg angle, 2θ.

FIG. 21 is a graph of CO and hydrocarbon conversion versus temperaturebased on Example 30.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention relates to apparatus and methods for cleaning theatmosphere useful with vehicles having means to convey the vehiclethrough the atmosphere. As the vehicle moves through the atmosphere, atleast one atmosphere contacting surface comprising a pollutant treatingcomposition (e.g., a catalyst or an adsorber) located thereon contactsatmospheric air. As the atmospheric air encounters the pollutanttreating composition, various pollutants including particulate matterand/or gaseous pollutants carried in the air can be catalyticallyreacted or adsorbed by the pollutant treating composition located on theatmosphere contacting surface.

It will be appreciated by those skilled in the art that the vehicle canbe any suitable vehicle which has a translation means to propel thevehicle such as wheels, sails, belts, tracks or the like. Such means canbe powered by any suitable power means including engines which usefossil fuel such as gasoline or diesel fuel, ethanol, methanol, gasengines powered by fuels such as by methane gas, wind power such as bywind driving sails or propellers, solar power or electric power such asin battery operated automobiles. Vehicles include cars, trucks, buses,trains, boats, ships, airplanes, dirigibles, balloons and the like.

The atmosphere contacting surface can be any suitable surface thatencounters and contacts air as the vehicle moves through the atmosphere.Preferably in a motor vehicle, preferably cars, trucks and buses, thecontact means is a surface located toward the front of the vehicle andcan contact air as the vehicle proceeds in a forward direction. Usefulcontact surfaces should have a relatively large surface area. Preferredcontact surfaces are at least partially enclosed in the vehicle.Preferred atmosphere contacting surfaces are located under the hood andare located within the body of the motor vehicle, typically in proximityto the engine, i.e., the engine compartment. The surfaces are preferablythe outer surfaces of cooling means which comprise a flow path forliquids or gases through a coolant walled enclosure such as tubes or ahousing and an outer surface on which is located fins to enhance heattransfer. Useful contact surfaces include the outside surfaces of meansto cool fluids, including liquids and/or gases used in the vehicle suchas the air conditioner condenser, the radiator, air charge cooler,engine oil cooler, transmission oil cooler, power steering fluid cooler,the fan shroud, and the radiator fan which are all located and supportedwithin the housing of the vehicle. A useful contact surface outside ofthe vehicle can be the grill typically located and supported on thefront of the housing, or wind deflectors commonly supported on the roofof the cabs of large trucks. It is preferred that the contacting surfaceis a forward facing surface, side facing surface or surface facing thetop or bottom of the vehicle. The front facing surfaces face the frontof the vehicle, surfaces such as the fins of the radiator and condenserelements face the side, top and bottom of the vehicle. Even surfacesdirected to face away from the front and toward the back of the vehiclewhich contact air can be atmosphere contacting surfaces, such as theback surface of fan blades. Surfaces of airplane engines such as wings,propellers and jet engine parts including turbine rotors and/or statorscan be coated.

Preferred atmosphere contacting surfaces in motor vehicles are locatedon engine cooling elements such as motor vehicle radiators, airconditioner condensers, air charge coolers, also known as intercoolersor after coolers, engine oil coolers and transmission oil coolers. Suchelements typically have high surface area structures associated withthem to have improved heat transfer. The high surface areas are usefulfor maximizing the contact of the atmospheric air with the pollutanttreating composition. All such elements are well known in the automotivearts. Reference is made to Bosch Automotive Handbook, Second Edition,pages 301-303, 320 and 349-351, published by Robert Bosch GmbH, 1986,herein incorporated by reference. This reference illustrates a truckdiesel engine with a radiator, an intercooler and a fan. Such elementsmay be coated with a pollutant treating surface of the presentinvention. The radiator and intercooler typically operate attemperatures higher than that of the atmospheric air. Reference is alsomade to Taylor, The Internal Combustion Engine in Theory and Practice,Vol. 1: Thermo Dynamics, Fluid Flow, Performance, Second Edition, Rev.The MIT Press, 1985 at pages 304-306 for radiator and fin design; andpage 392 for after coolers. The above pages in Taylor are hereinincorporated by reference.

Reference is also made to a collection of papers in 1993 Vehicle ThermalManagement Systems Conference Proceedings, SAE P:263 published by theSociety of Automotive Engineers, Inc., 1993. The following papers areherein incorporated by reference. SAE Paper No. 931088 beginning at page157 entitled, Calculation and Design of Cooling Systems by Eichlsederand Raab of Steyr Damler Puchag and Charge Air Cooler for Passenger Carsby Collette of Valeo Thermique Moteur; SAE Paper No. 931092 entitled,State of the Art and Future Developments of Aluminum Radiators for Carsand Trucks by Kern and Eitel of Behr GmbH and Co. beginning at page 187;SAE Paper 931112 entitled, Air Mix vs. Coolant Flow to Control DischargeAir Temperature and Vehicle Heating Air Conditioning Systems by Rollingand Cummings of Behr of America, Inc. and Schweizer of Behr GmbH & Co.The above papers include descriptions of radiator, air conditioner andair charge cooler structures for use in the motor vehicles. Reference isadditionally made to SAE Paper 931115 entitled, Engine Cooling ModuleDevelopment Using Air Flow Management Techniques by El-Bourini and Chenof Calsonic Technical Center beginning at page 379 and herebyincorporated by reference. Of interest are Appendices 1 and 2 whichillustrate typical radiator and condenser structures useful in motorvehicle applications. Reference is also made to SAE Paper 931125entitled, Durability Concerns of Aluminum Air to Air Charged Coolers bySmith, Valeo Engine Cooling Inc. which discloses air charge coolers andis hereby incorporated by reference.

The present invention will be understood by those skilled in the art byreference to the accompanying FIGS. 1-7.

FIG. 1 illustrates a truck 10 schematically containing a variety ofvehicle components comprising atmosphere contacting surfaces. Thesesurfaces include the surfaces of grill 12, the air conditioner condenser14, an air charge cooler 25, the radiator 16, and the radiator fan 18.Also shown on this truck is a wind deflector 20 having a frontdeflecting surface 22. It is recognized that the various components canhave different relative locations on different vehicles.

Referring to FIGS. 1 to 4 the preferred contacting surfaces include thesurface of the front 13 and side 15 surfaces of the air conditionercondenser 14, the front 17 and side 19 surfaces of the radiator 16,corresponding surfaces of the air charge cooler 25 and the front 21 andback 23 surfaces of the radiator fan 18. These surfaces are locatedwithin the housing 24 of the truck. They are typically under the hood 24of the truck between the front 26 of the truck and the engine 28. Theair conditioner condenser, air charge cooler, radiator and radiator fancan be directly or indirectly supported by housing 24 or a frame (notshown) within the housing.

FIG. 2 generally shows a schematic view of an automobile assembly.Corresponding elements in FIGS. 1 and 2 have common referencecharacters. The automobile comprises a housing 30. There is a motorvehicle front 32 having a grill 12 supported on the front of the housing30. An air conditioner condenser 14, a radiator 16, and a radiator fan18 can be located within the housing 30.

Referring to embodiments in FIGS. 1, 2 and 6, the contacting surface onthe front and sides of least one of the grill 12, air conditionercondenser 14, the air charge cooler 25, and radiator 16; the front andback of the radiator fan 18; and the front of the wind deflector 20 canhave a pollutant treating composition located thereon. The grill 12 canhave a suitable grill grid type design which provides for openings 36through which air passes as the truck 12 is operated and moves throughthe atmosphere. The openings are defined by the grill grid 38. The grillgrid 38 has a front grill surface 40 and a side grill surface 42. Thefront and side grill grid surfaces 40 and 42 can be used as atmospherecontacting surfaces on which pollutant treating compositions arelocated.

Referring to FIGS. 1 and 4, the air conditioning condenser 14 comprisesa plurality of air conditioning condenser fins 44. Additionally, thereis an air conditioning fluid conduit 46 which conducts the airconditioning fluid through condenser 14. The front and side surfaces ofthe air conditioning fins 44, as well as the front surface of the airconditioning conduit 46 can be the atmosphere contacting surfaces onwhich a pollutant treating composition is located. As indicated, boththe front 21 and back 23 surfaces of the radiator fan 18 can be acontacting surface to support a pollutant treating composition.

The most preferred atmosphere contacting surface is on radiator 16 asshown in FIG. 3. A typical radiator 16 has a frontal radiator surface 17as well as a plurality of radiator corrugated plates or fins 50 locatedin corresponding radiator plate or fin channels 52 which pass throughthe radiator 16. It is preferred to coat the front surface 17 as well asthe side surfaces of the radiator plates 50 and channel 52 surfaces. Theradiator is most preferred because it is located within the housing 24or 30 and is protected from the front by at least the grill 12 andpreferably an air conditioner condenser 14. In addition to air enteringinto the hood chamber 34 as the motor vehicle moves through theatmosphere, radiator fan 18 draws air in and through the channels 52.Therefore, the radiator 16 is located and protected by the grill 12, theair conditioner condenser 19 and is in front of the radiator fan 18.Additionally, as indicated above, the radiator has a large surface areafor heat transfer purposes. In accordance with the present invention,pollutant treating composition can be effectively located on, and takeadvantage of, such a large surface area without significantly adverselyimpacting on the heat transfer function of the radiator.

The above description is particularly directed to and illustrates theuse of atmosphere treating surfaces on apparatus such as radiator 16 andair conditioner condenser 14. As indicated the atmosphere contactingsurface can be on other suitable means to cool engine fluids includingwell known articles such as the above referenced air charge cooler 25 aswell as engine oil coolers, transmission oil coolers and power steeringoil coolers. A commonality of all such cooling means is a housing orconduit through which the fluid passes. The housing comprises a wallhaving an inner surface in contact with the fluid and an outer surfacetypically in contact with the atmosphere within the frame of the vehicleand typically within the engine compartment. In order to efficientlytransfer heat from the fluid in these various apparatus, there are finsor plates extending from the outer surface of the cooling, housing orconduit.

A useful and preferred embodiment with each of these cooling means isillustrated in FIG. 7. FIG. 7 is a schematic sectional view of a coatedfinned cooling element 60. The element comprises a housing or conduitdefined by a housing or conduit wall 62. Located within the conduit is apassageway or chamber 64 through which fluid such as oils or coolingliquids or air conditioning fluids pass. Such fluids are shown asreferenced character 66. The housing wall comprises an inner surface 68and an outer surface 70. Located and attached to the outer surface areplates or fins 72. In accordance with the present invention, there is apollutant treating composition 74 which can be located on the outersurface 70 and the fins or plates 72. During operation air streamscontact the pollutant treating composition to cause various of thepollutants to be treated.

Applicant herein incorporates by reference commonly assigned patentapplication entitled, “Pollution Treating Device and Methods of Makingthe Same”, filed as U.S. Ser. No. 08/537,208. Additionally, any of theembodiments of the apparatus of the present invention and method of usethereof can optionally further incorporate a replaceable pollutiontreating device as disclosed therein.

Pollutant treating compositions can also be located on outer surfaces ofthe vehicle. As indicated, such compositions can be located on the grill12 and in the case of the truck shown in FIGS. 1 and 6, on the winddeflector 20 frontal wind deflector surface 22. Additionally, pollutiontreatment compositions can be located on the front of the mirror 54 aswell as any of a variety of front facing surfaces.

The use of an air charge cooler 25 represents a particularly effectiveatmosphere contacting surface on which pollutant treating compositionscan be supported. The operating temperatures can reach as high as 250°F. At such temperatures, the catalyst compositions of the presentinvention can more effectively treat ozone, hydrocarbons, and carbonmonoxide pollutants. Particularly useful are compositions containingprecious metals such as platinum, palladium, gold or silver components.Alternatively, the catalyst can include manganese compounds such asmanganese dioxide and copper compounds including copper oxide suchCARULITE® catalyst or hopcalite.

During normal operation, the vehicle moves in a forward direction withthe front 26 of the vehicle 10 initially contacting the atmospheric air.Typically, vehicles move through the air at velocities of up to about1,000 miles per hour for jet planes. Land vehicles and water vehiclestypically move at velocities of up to 300 miles per hour, more typicallyup to 200 miles per hour with motor vehicles moving at velocities up to100 miles per hour and typically from 5 to 75 miles per hour. Seagoingvehicles, such as boats, typically move through the water at velocitiesup to 30 miles per hour and typically from 2 to 20 miles per hour. Inaccordance with method of the present invention the relative velocity(or face velocity) between the atmosphere contacting surface and theatmosphere, as the vehicle, typically an automobile or land basedvehicle, moves through the atmosphere, is from 0 to 100 miles per hour,and typically from 2 to 75 miles per hour in an automobile typicallyfrom 5 to 60 miles per hour. The face velocity is the velocity of theair relative to the pollutant treating surface.

In motor vehicles such as trucks 10 which have a radiator fan 18, thefan draws atmospheric air through the grill 12, air conditionercondenser 14, air charge cooler 25 and/or radiator 16 in addition to airwhich passes across these elements as the motor vehicle moves throughthe atmosphere. When the motor vehicle is idling the relative facevelocity of air drawn into the radiator typically ranges from about 5 to15 mph. The radiator fan moderates the flow rate of air through radiatoras the motor vehicle moves through the atmosphere. When a typical car ismoving through the atmosphere at speeds approaching 70 mph, the inletface velocity of air is at about 25 mph. Depending on the design of amotor vehicle using a radiator fan, cars have a face velocity as low aswhen the fan is used during idle up to about 100% of the face velocitycorresponding to the velocity of the motor vehicle. However, typically,the face velocity of the air relative to the atmosphere contactingsurface is equal to the idle face velocity plus from 0.1 to 1.0 and moretypically 0.2 to 0.8 times the velocity of the vehicle.

In accordance with the present invention, large volumes of air can betreated at relatively low temperatures. This occurs as vehicles movethrough the atmosphere. High surface area components of vehiclesincluding radiators, air conditioner condensers and charge air coolerstypically have a large frontal surface area which encounters the airstream. However, these devices are relatively narrow, typically rangingfrom about ¾ of an inch deep up to about 2 inches deep and usually inthe range of ¾ to 1½ inches deep. The linear velocity of the atmosphericair contacting the frontal surface of such devices is typically in therange of up to 20, and more typically 5 to 15 miles per hour. Anindication of the amount of air being treated as it passes across thecatalyzed vehicle component is commonly referred to space velocity ormore precisely volume hourly space velocity (VHSV). This is measured asvolume (corresponding to the volume of the catalyzed element) of air perhour which passes across the volume of the catalytic article. It isbased on the cubic feet per hour of air divided by the cubic feet ofcatalyst substrate. The volume of the catalyst substrate is the frontalarea times the depth or axial length in the direction of the air flow.Alternatively, volume hourly space velocity is the number of catalystvolumes based on the volume of the catalytic article being treated-perhour. Because of the relatively short axial depth of the catalyzedelements of the present invention, the space velocities are relativelyhigh. The volume hourly space velocities of air which can be treated inaccordance with the present invention can be a million or morereciprocal hours. A face velocity of air against one of these elementsat 5 miles per hour can result in a space velocity of as high as 300,000reciprocal hours. In accordance with the present invention, thecatalysts are designed to treat pollutants in the atmosphere at spacevelocities in ranges as high as from 250,000 to 750,000 and typically300,000 to 600,000 reciprocal hours. This is accomplished even at therelatively low ambient temperatures and ambient operating temperaturesof the vehicle elements containing pollutant treating compositions inaccordance with the present invention.

The ambient operating temperature of the atmosphere contacting surfacescan vary depending on whether they are located in the proximity of heatsources within the vehicle or are the surfaces of elements whichfunction to cool parts of the vehicle. However, contacting surfaces suchas grill 12, wind deflector 20 are at ambient conditions. During typicaloperation, the means to cool operates at above ambient atmospherictemperature, with the contacting surfaces such as the surfaces of theair conditioner condenser 14, and radiator 16 and air charge cooler 25can range up to 130° C. and typically up to 105° C. and are typically inthe range of from 10° C. to 105° C., more typically from 40° C. to 100°C. and can be from 10° C. to 75° C. The air charge cooler 25 typicallyoperates at temperatures of from 75° to 130° C. The amount of contactingsurface can vary with air conditioner condensers, radiators and aircharge coolers typically having from 20 to 2,000 square feet and fanblades 18 typically having from 0.2 to up to about 40 square feet whenconsidering front and back surfaces.

The pollutant treating composition is preferably a catalytic compositionor adsorption composition. Useful and preferred catalyst compositionsare compositions which can catalytically cause the reaction of targetedpollutants at the space velocity of the air as it contacts the surface,and at the temperature of the surface at the point of contact.Typically, these catalyzed reactions will be in the temperature range atthe atmosphere contacting surface of from 0° C. to 130° C., moretypically 20° C. to 105° C. and yet more typically from about 40° C. to100° C. There is no limit on the efficiency of the reaction as long assome reaction takes place. Preferably, there is at least a 1% conversionefficiency with as high a conversion efficiency as possible. Usefulconversion efficiencies are preferably at least about 5% and morepreferably at least about 10%. Preferred conversions depend on theparticular pollutant and pollutant treating composition. Where ozone istreated with a catalytic composition on an atmosphere contacting surfaceit is preferred that the conversion efficiency be greater than aboutfrom 30% to 40%, preferably greater than 50%, and more preferablygreater than 70%. Preferred conversion for carbon monoxide is greaterthan 30% and preferably greater than 50%. Preferred conversionefficiency for hydrocarbons and partially oxygenated hydrocarbons is atleast 10%, preferably at least 15%, and most preferably at least 25%.These conversion rates are particularly preferred where the atmospherecontacting surface is at ambient operating conditions of up to about110° C. These temperatures are the surface temperatures typicallyexperienced during normal operation of atmosphere contacting surfaces ofthe vehicle including the surfaces of the radiator and air conditioningcondenser. Where there is supplemental heating of the atmospherecontacting surface such as by having an electrically heated catalyticmonolith, grid, screen, gauze or the like, it is preferred that theconversion efficiency be greater than 90% and more preferably greaterthan 95%. The conversion efficiency is based on the mole percent of theparticular pollutants in the air which react in the presence of thecatalyst composition.

Ozone treating catalyst compositions comprise manganese compoundsincluding manganese dioxide, including non stoichiometric manganesedioxide (e.g., MnO_((1.5-2.0))), and/or Mn₂O₃. Preferred manganesedioxides, which are nominally referred to as MnO₂ have a chemicalformula wherein the molar ratio of manganese to oxide is about from 1.5to 2.0, such as Mn₈O₁₆. Up to 100 percent by weight of manganese dioxideMnO₂ can be used in catalyst compositions to treat ozone. Alternativecompositions which are available comprise manganese dioxide andcompounds such as copper oxide alone or copper oxide and alumina.

Useful and preferred manganese dioxides are alpha manganese dioxidesnominally having a molar ratio of manganese to oxygen of from 1 to 2.Useful alpha manganese dioxides are disclosed in U.S. Pat. No. 5,340,562to O'Young, et al.; also in O'Young, Hydrothermal Synthesis of ManganeseOxides with Tunnel Structures presented at the Symposium on Advances inZeolites and Pillared Clay Structures presented before the Division ofPetroleum Chemistry, Inc. American Chemical Society New York CityMeeting, Aug. 25-30, 1991 beginning at page 342, and in McKenzie, theSynthesis of Birnessite, Cryptomelane, and Some Other Oxides andHydroxides of Manganese, Mineralogical Magazine, December 1971, Vol. 38,pp. 493-502. For the purposes of the present invention, the preferredalpha manganese dioxide is a 2×2 tunnel structure which can behollandite (BaMn₈O₁₆.xH₂O), cryptomelane (KMn₈O₁₆.xH₂O), manjiroite(NaMn₈O₁₆.xH₂O) and coronadite (PbMn₈O₁₆. xH₂O).

The manganese dioxides of the present invention preferably have asurface area, measured by BET N₂ adsorption, of greater than 150 m²/g,more preferably greater than 200 m²/g, and more preferably greater than220 m²/g. The upper range can be as high as 300 m²/g, 325 m²/g or even350 m²/g. Preferred materials are in the range of 200-350 m²/g,preferably 200-275 m²/g and most preferably 220-250 m²/g. Thecomposition preferably comprises a binder as described below withpreferred binders being polymeric binders. The composition can furthercomprise precious metal components with preferred precious metalcomponents being the oxides of precious metal, preferably the oxides ofplatinum group metals and most preferably the oxides of palladium orplatinum also referred to as palladium black or platinum black. Theamount of palladium or platinum black can range from 0 to 25%, withuseful amounts being in ranges of from about 1 to 25 and 5 to 15% byweight based on the weight of the manganese component and the preciouscomponent.

It has been found that the use of compositions comprising thecryptomelane form of alpha manganese oxide, which also contain apolymeric binder can result in greater than 50%, preferably greater than60% and most preferably from 75-85% conversion of ozone in aconcentration range of from 0 to 400 parts per billion (ppb) and an airstream moving across a radiator at space velocity of from 300,000 to650,000 reciprocal hours. Where a portion of the cryptomelane isreplaced by up to 25% and preferably from 15-25% parts by weight ofpalladium black (PdO), ozone conversion rates at the above conditionsrange from 95-100% using a powder reactor.

The preferred cryptomelane manganese dioxide has from 1.0 to 3.0 weightpercent potassium, typically as K₂O, and a crystallite size ranging from2 to 10 and preferably from less than 5 nm. It can be calcined at atemperature range of from 250° C. to 550° C. and preferably below 500°C. and greater than 300° C. for at least 1.5 hours and preferably atleast 2 hours up to about 6 hours.

The preferred cryptomelane can be made in accordance described in theabove referenced articles and patents to O'Young and McKenzie. Thecryptomelane can be made by reacting a manganese salt including saltsselected from the group consisting MnCl₂, Mn(NO₃)₂, MnSO₄ andMn(CH₃COO)₂ with a permanganate compound. Cryptomelane is made usingpotassium permanganate; hollandite is made using barium permanganate;coronadite is made using lead permanganate; and manjiroite is made usingsodium permanganate. It is recognized that the alpha manganese useful inthe present invention can contain one or more of hollandite,cryptomelane, manjiroite or coronadite compounds. Even when makingcryptomelane minor amounts of other metal ions such as sodium may bepresent. Useful methods to form the alpha manganese dioxide aredescribed in the above references which are incorporated by reference.

The preferred alpha manganese for use in accordance with the presentinvention is cryptomelane. The preferred cryptomelane is “clean” orsubstantially free of inorganic anions, particularly on the surface.Such anions could include chlorides, sulfates and nitrates which areintroduced during the method to form cryptomelane. An alternate methodto make the clean cryptomelane is to react a manganese carboxylate,preferably manganese acetate, with potassium permanganate. It has beenfound that the use of such a material which has been calcined is“clean”. The use of material containing inorganic anions can result inconversion of ozone to oxygen of up to about 60%. The use ofcryptomelane with a “clean” surface results in conversions of up about80%.

It is believed that the carboxylates are burned off during thecalcination process. However, inorganic anions remain on the surfaceeven during calcination. The inorganic anions such as sulfates can bewashed away with an aqueous solution or a slightly acidic aqueoussolution. Preferably the alpha manganese dioxide is a “clean” alphamanganese dioxide. The cryptomelane can be washed at from about 60° C.to 100° C. for about one-half hour to remove a significant amount ofsulfate anions. The washing also lowers the level of potassium present.The nitrate anions may be removed in a similar manner. The “clean” alphamanganese dioxide is characterized as having an IR spectrum asillustrated in FIG. 19 and in X-ray diffraction (XRD) pattern asillustrated in FIG. 20. Such a cryptomelane preferably has a surfacearea greater than 200 m²/g and more preferably greater than 250 m²/g. Areview of the IR spectrum for the most preferred cryptomelane, shown inFIG. 19 is characterized by the absence of peaks assignable tocarbonate, sulfate and nitrate groups. Expected peaks for carbonategroups appear in the range of from 1320 to 1520 wavenumbers; and forsulfate groups appear in the range of from 950 to 1250 wavenumbers. FIG.20 is a powder X-ray diffraction pattern for high surface areacryptomelane prepared in Example 23. The X-ray pattern for cryptomelaneuseful in the present invention is characterized by broad peaksresulting from small crystallite size (˜5-10 nm). Approximate peakpositions (±0.15°2θ) and approximate relative intensities (±5) forcryptomelane using CuK_(α), radiation as shown in FIG. 20 are:2θ/Relative Intensities—12.1/9; 18/9; 28.3/10; 37.5/100; 41.8/32;49.7/16; 53.8/5; 60.1/13; 55.7/38; and 68.0/23.

A preferred method of making cryptomelane useful in the presentinvention comprises mixing an aqueous acidic manganese salt solutionwith a potassium permanganate solution. The acidic manganese saltsolution preferably has a pH of from 0.5 to 3.0 and can be made acidicusing any common acid, preferably acetic acid at a concentration of from0.5 to 5.0 normal and more preferably from 1.0 to 2.0 normal. Themixture forms a slurry which is stirred at a temperature range of from50° C. to 110° C. The slurry is filtered and the filtrate is dried at atemperature range of from 75° C. to 200° C. The resulting cryptomelanecrystals have a surface area of typically in the range of from 200 m²/gto 350 m²/g.

Another useful composition comprising manganese dioxide is a compositioncomprising manganese dioxide and minor amounts of silica, typically upto 2%, more typically up to 1% with preferred amounts being from 0.4 to0.8% based on the weight of the manganese dioxide and the silica. Thepresence of silica in the preferred amounts has been found to effect thecrystalline morphology of manganese dioxide, particularly thecryptomelane form of manganese dioxide. It is speculated that thepresence of minor amounts of silica, particularly in the preferredrange, may provide certain advantages to the composition of the presentinvention. The presence of silica is believed to make the compositionmore hydrophobic, particularly when used as a coating on a substratesuch as a coating on a radiator. Secondly, it is believed that thepresence of silica in coating compositions comprising manganese dioxideincreases the pH to help the compatibility of the manganese dioxide withlatex binders. A preferred and useful composition for use as a coatingmaterial comprises cryptomelane and silica. Such a material comprisescryptomelane having a surface area from 200 to 340 and preferably 220 to250 m²/g, a weight percent of potassium of from 1 to 3% less than 0.1%sulphur and a measured loss on ignition of 13 to 18% by weight primarilydue to moisture. The pH of the composition is about 3. Surface area ismeasured by a BET nitrogen adsorption and desorption test. As the amountof sulphur is reduced, the pH typically increases slightly.Additionally, typically the pH increases with the amount of potassiumpresent with preferred amounts of potassium being from 1.2 to 2.8 weightpercent.

Other useful compositions comprise manganese dioxide and optionallycopper oxide and alumina and at least one precious metal component suchas a platinum group metal supported on the manganese dioxide and wherepresent copper oxide and alumina. Useful compositions contain up to 100,from 40 to 80 and preferably 50 to 70 weight percent manganese dioxideand 10 to 60 and typically 30 to 50 percent copper oxide. Usefulcompositions include hopcalite which is about 60 percent manganesedioxide and about 40 percent copper oxide; and CARULITE® 200 catalyst(sold by Carus Chemical Co.) which is reported to have 60 to 75 weightpercent manganese dioxide, 11 to 14 percent copper oxide and 15 to 16percent aluminum oxide. The surface area of CARULITE® catalyst isreported to be about 180 m²/g. Calcining at 450° C. reduces the surfacearea of the CARULITE® catalyst by about fifty percent (50%) withoutsignificantly affecting activity. It is preferred to calcine manganesecompounds at from 300° C. to 500° C. and more preferably 350° C. to 450°C. Calcining at 550° C. causes a great loss of surface area and ozonetreatment activity. Calcining the CARULITE® catalyst after ball millingwith acetic acid and coating on a substrate can improve adhesion of thecoating to a substrate.

Other compositions to treat ozone can comprise a manganese dioxidecomponent and precious metal components such as platinum group metalcomponents. While both components are catalytically active, themanganese dioxide can also support the precious metal component. Theplatinum group metal component preferably is a palladium and/or platinumcomponent. The amount of platinum group metal compound preferably rangesfrom about 0.1 to about 10 weight percent (based on the weight of theplatinum group metal) of the composition. Preferably, where platinum ispresent it is in amounts of from 0.1 to 5 weight percent, with usefuland preferred amounts on pollutant treating catalyst volume, based onthe volume of the supporting article, ranging from about 0.5 to about 70g/ft³. The amount of palladium component preferably ranges from about 2to about 10 weight percent of the composition, with useful and preferredamounts on pollutant treating catalyst volume ranging from about 10 toabout 250 g/ft³.

Various useful and preferred pollutant treating catalyst compositions,especially those containing a catalytically active component such as aprecious metal catalytic component, can comprise a suitable supportmaterial such as a refractory oxide support. The preferred refractoryoxide can be selected from the group consisting of silica, alumina,titania, ceria, zirconia and chromia, and mixtures thereof. Morepreferably, the support is at least one activated, high surface areacompound selected from the group consisting of alumina, silica, titania,silica-alumina, silica-zirconia, alumina silicates, alumina zirconia,alumina-chromia and alumina-ceria. The refractory oxide can be insuitable form including bulk particulate form typically having particlesizes ranging from about 0.1 to about 100 and preferably 1 to 10 μm orin sol form also having a particle size ranging from about 1 to about 50and preferably about 1 to about 10 nm. A preferred titania sol supportcomprises titania having a particle size ranging from about 1 to about10, and typically from about 2 to 5 nm.

Also useful as a preferred support is a coprecipitate of a manganeseoxide and zirconia. This composition can be made as recited in U.S. Pat.No. 5,283,041 incorporated herein by reference. Briefly, thiscoprecipitated support material preferably comprises in a ratio based onthe weight of manganese and zirconium metals from 5:95 to 95:5;preferably 10:90 to 75:25; more preferably 10:90 to 50:50; and mostpreferably from 15:85 to 50:50. A useful and preferred embodimentcomprises a Mn:Zr weight ratio of 20:80. U.S. Pat. No. 5,283,041describes a preferred method to make a coprecipitate of a manganeseoxide component and a zirconia component. As recited in U.S. Pat. No.5,283,041 a zirconia oxide and manganese oxide material may be preparedby mixing aqueous solutions of suitable zirconium oxide precursors suchas zirconium oxynitrate, zirconium acetate, zirconium oxychloride, orzirconium oxysulfate and a suitable manganese oxide precursor such asmanganese nitrate, manganese acetate, manganese dichloride or manganesedibromide, adding a sufficient amount of a base such as ammoniumhydroxide to obtain a pH of 8-9, filtering the resulting precipitate,washing with water, and drying at 450°-500° C.

A useful support for a catalyst to treat ozone is selected from arefractory oxide support, preferably alumina and silica-alumina with amore preferred support being a silica-alumina support comprising fromabout 1% to 10% by weight of silica and from 90% to 99% by weight ofalumina.

Useful refractory oxide supports for a catalyst comprising a platinumgroup metal to treat carbon monoxide are selected from alumina, titania,silica-zirconia, and manganese-zirconia. Preferred supports for acatalyst composition to treat carbon monoxide is a zirconia-silicasupport as recited in U.S. Pat. No. 5,145,825, a manganese-zirconiasupport as recited in U.S. Pat. No. 5,283,041 and high surface areaalumina. Most preferred for treatment of carbon monoxide is titania.Reduced catalysts having titania supports resulted in greater carbonmonoxide conversion than corresponding non reduced catalysts.

The support for catalyst to treat hydrocarbons, such as low molecularweight hydrocarbons, particularly low molecular weight olefinichydrocarbons having about from two up to about twenty carbons andtypically two to about eight carbon atoms, as well as partiallyoxygenated hydrocarbons is preferably selected from refractory metaloxides including alumina and titania. As with catalysts to treat carbonmonoxide reduced catalysts results in greater hydrocarbon conversion.Particularly preferred is a titania support which has been found usefulsince it results in a catalyst composition having enhanced ozoneconversion as well as significant conversion of carbon monoxide and lowmolecular weight olefins. Also useful are high surface area, macroporousrefractory oxides, preferably alumina and titania having a surface areaof greater than 150 m²/g and preferably ranging from about 150 to 350,preferably from 200 to 300, and more preferably from 225 to 275 m²/g; aporosity of greater than 0.5 cc/g, typically ranging from 0.5 to 4.0 andpreferably about from 1 to 2 cc/g measured based on mercury porosometry;and particle sizes range from 0.1 to 10 μm. A useful material is VersalGL alumina having a surface area of about 260 m²/g, a porosity of 1.4 to1.5 cc/g and supplied by LaRoche Industries.

A preferred refractory support for platinum group metals, preferablyplatinum and/or palladium for use in treating carbon monoxide and/orhydrocarbons is titania dioxide. The titania can be used in bulk powderform or in the form of titania dioxide sol. Also useful is nano particlesize (nanometer) titania. The catalyst composition can be prepared byadding a platinum group metal in a liquid media preferably in the formof a solution such as platinum nitrate with the titania sol, with thesol most preferred. The obtained slurry can then be coated onto asuitable substrate such as an atmosphere treating surface such as aradiator, metal monolith substrate or ceramic substrate. The preferredplatinum group metal is a platinum compound. The platinum titania solcatalyst obtained from the above procedure has high activity for carbonmonoxide and/or hydrocarbon oxidation at ambient operating temperature.Metal components other than platinum components which can be combinedwith the titania sol include gold, palladium, rhodium, silver componentsand mixtures thereof. A reduced platinum group component, preferably aplatinum component on titanium catalyst which is indicated to bepreferred for treating carbon monoxide, has also been found to be usefuland preferred for treating hydrocarbons, particularly olefinichydrocarbons.

A preferred titania sol support comprises titania having a particle sizeranging from about 1 to about 10, and typically from about 2 to 5 nm.

A preferred bulk titania has a surface area of about from 25 to 120m²/g, and preferably from 50 to 100 m²/g; and a particle size of aboutfrom 0.1 to 10 μm. A specific and preferred bulk titania support has asurface area of 45-50 m²/g, a particle size of about 1 μm, and is soldby DeGussa as P-25. Useful nano particle size titanium comprises havinga particle size ranging from about 5 to 100 and typically greater 10 toabout 50 nm.

A preferred silica-zirconia support comprises from 1 to 10 percentsilica and 90 to 99 percent zirconia. Preferred support particles havehigh surface area, e.g. from 100 to 500 square meters per gram (m²/g)surface area, preferably from 150 to 450 m²/g, more preferably from 200to 400 m²/g, to enhance dispersion of the catalytic metal component orcomponents thereon. The preferred refractory metal oxide support alsohas a high porosity with pores of up to about 145 nm radius, e.g., fromabout 0.75 to 1.5 cubic centimeters per gram (cm³/g), preferably fromabout 0.9 to 1.2 cm³/g, and a pore size range of at least about 50% ofthe porosity being provided by pores of 5 to 100 nm in radius.

A useful ozone treating catalyst comprises at least one precious metalcomponent, preferably a palladium component dispersed on a suitablesupport such as a refractory oxide support. The composition comprisesfrom 0.1 to 20.0 weight percent, and preferably 0.5 to 15 weight percentof precious metal on the support, such as a refractory oxide support,based on the weight of the precious metal (metal and not oxide) and thesupport. Palladium is preferably used in amounts of from 2 to 15, morepreferably 5 to 15 and yet more preferably 8 to 12 weight percent.Platinum is preferably used at 0.1 to 10, more preferably 0.1 to 5.0,and yet more preferably 2 to 5 weight percent. Palladium is mostpreferred to catalyze the reaction of ozone to form oxygen. The supportmaterials can be selected from the group recited above. In preferredembodiments, there can additionally be a bulk manganese component asrecited above, or a manganese component dispersed on the same ordifferent refractory oxide support as the precious metal, preferablypalladium component. There can be up to 80, preferably up to 50, morepreferably from 1 to 40 and yet more preferably 5 to 35 weight percentof a manganese component based on the weight of palladium and manganesemetal in the pollutant treating composition. Stated another way, thereis preferably about 2 to 30 and preferably 2 to 10 weight percent of amanganese component. The catalyst loading is from 20 to 250 grams andpreferably about 50 to 250 grams of palladium per cubic foot (g/ft³) ofcatalyst volume. The catalyst volume is the total volume of the finishedcatalyst composition and therefore includes the total volume of airconditioner condenser or radiator including void spaces provided by thegas flow passages. Generally, the higher loading of palladium results ina greater ozone conversion, i.e., a greater percentage of ozonedecomposition in the treated air stream.

Conversions of ozone to oxygen attained with a palladium/manganesecatalyst on alumina support compositions at a temperature of about 40°C. to 50° C. have been about 50 mole percent where the ozoneconcentrations range from 0.1 to 0.4 ppm and the face velocity was about10 miles per hour. Lower conversions were attained using a platinum onalumina catalyst.

Of particular interest is the use of a support comprising the abovedescribed coprecipitated product of a manganese oxide, and zirconiawhich is used to support a precious metal, preferably selected fromplatinum and palladium, and most preferably platinum. Platinum is ofparticular interest in that it has been found that platinum isparticularly effective when used on this coprecipitated support. Theamount of platinum can range from 0.1 to 6, preferably 0.5 to 4, morepreferably 1 to 4, and most preferably 2 to 4 weight percent based onmetallic platinum and the coprecipitated support. The use of platinum totreat ozone has been found to be particularly effective on this support.Additionally, as discussed below, this catalyst is useful to treatcarbon monoxide. Preferably the precious metal is platinum and thecatalyst is reduced.

Other useful catalysts to catalytically convert ozone to oxygen aredescribed in U.S. Pat. Nos. 4,343,776 and 4,405,507, both herebyincorporated by reference. A useful and most preferred composition isdisclosed in commonly assigned U.S. Ser. No. 08/202,397 filed Feb. 25,1994, now U.S. Pat. No. 5,422,331 and entitled, “Light Weight, LowPressure Drop Ozone Decomposition Catalyst for Aircraft Applications”hereby incorporated by reference. Yet other compositions which canresult in the conversion of ozone to oxygen comprises carbon, andpalladium or platinum supported on carbon, manganese dioxide, CARULITE®catalyst, and/or hopcalite. Manganese supported on a refractory oxidesuch as recited above has also been found to be useful.

Carbon monoxide treating catalysts preferably comprise at least oneprecious metal component, preferably selected from platinum and/orpalladium components with platinum components being most preferred. Acombination of a platinum component and a palladium component results inimproved CO conversion at an increase in cost and is most preferredwhere greater conversion is desired and cost increase is acceptable. Thecomposition comprises from 0.01 to 20 weight percent, and preferably 0.5to 15 weight percent of the precious metal component on a suitablesupport such as refractory oxide support, with the amount of preciousmetal being based on the weight of precious metal (metal and not themetal component) and the support. Platinum is most preferred and ispreferably used in amounts of from 0.01 to 10 weight percent and morepreferably 0.1 to 5 weight percent, and most preferably 1.0 to 5.0weight percent. Palladium is useful in amounts from 2 to 15, preferably5 to 15 and yet more preferably 8 to 12 weight percent. The preferredsupport is titania, with titania sol most preferred as recited above.When loaded onto a monolithic structure such as a radiator or onto otheratmosphere contacting surfaces the catalyst loading is preferably about1 to 150, and more preferably 10 to 100 grams of platinum per cubic foot(g/ft³) of catalyst volume and/or 20 to 250 and preferably 50 to 250grams of palladium per g/ft³ of catalyst volume. When platinum andpalladium are used in combination, there is from about 25 to 100 g/ft³of platinum and 50 to 250 g/ft³ of palladium. A preferred compositioncomprises about 50 to 90 g/ft³ of platinum and 100 to 225 g/ft³ ofpalladium. Preferred catalysts are reduced. Conversions of 5 to 80 molepercent of carbon monoxide to carbon dioxide were attained using coatedcore samples from automotive radiator having from 1 to 6 weight percent(based on metal) of platinum on titania compositions at temperaturesfrom 25° to 90° C. where the carbon monoxide concentration was 15 to 25parts per million and the space velocity was 300,000 to 500,000reciprocal hours. Also, conversions of 5 to 65 mole percent of carbonmonoxide to carbon dioxide were attained using 1.5 to 4.0 weight percentplatinum on alumina support compositions at a temperature of about up to95° C. where the carbon monoxide concentration was about 15 parts permillion and the space velocity was about 300,000 reciprocal hours. Lowerconversions have been attained with palladium on a ceria support.

An alternate and preferred catalyst composition to treat carbon monoxidecomprises a precious metal component supported on the above describedcoprecipitate of a manganese oxide and zirconia. The coprecipitate isformed as described above. The preferred ratios of manganese to zirconiaare 5:95 to 95:5; 10:90 to 75:25; 10:90 to 50:50; and 15:85 to 25:75with a preferred coprecipitate having a manganese oxides to zirconia of20:80. The percent of platinum supported on the coprecipitate based onplatinum metal ranges from 0.1 to 6, preferably 0.5 to 4, morepreferably 1 to 4, and most preferably 2-4 weight percent. Preferablythe catalyst is reduced. The catalyst can be reduced in powder form orafter it has been coated onto a supporting substrate. Other usefulcompositions which can convert carbon monoxide to carbon dioxide includea platinum component supported on carbon or a support comprisingmanganese dioxide.

Catalysts to treat hydrocarbons, typically unsaturated hydrocarbons,more typically unsaturated mono-olefins having from two to about twentycarbon atoms and, in particular, from two to eight carbon atoms, andpartially oxygenated hydrocarbons of the type referred to above,comprise at least one precious metal component, preferably selected fromplatinum and palladium with platinum being most preferred. A combinationof a platinum component and a palladium component results in improvedhydrocarbons conversion at an increase in cost and is most preferredwhere greater conversion is desired and cost increase is acceptable.Useful catalyst compositions include those described for use to treatcarbon monoxide. Composition to treat hydrocarbons comprise from 0.01 to20 wt. % and preferably 0.5 to 15 wt. % of the precious metal componenton a suitable support such as a refractory oxide support, with theamount of precious metal being based on the weight of the preciousmetal, (not the metal component) and the support. Platinum is the mostpreferred and is preferably used in amounts of from 0.01 to 10 wt. % andmore preferably 0.1 to 5 wt. % and most preferably 1.0 to 5 wt. %. Whenloaded onto a monolithic structure such as a motor vehicle radiator oron to other atmospheric contacting surfaces, the catalyst loading ispreferably about 1 to 150, and more preferably 10 to 100 grams ofplatinum per cubic foot (g/ft³) of catalyst volume. When platinum andpalladium are used in combination, there is from about 25 to 100 g/ft³of platinum and 50 to 250 g/ft³ of palladium. A preferred compositioncomprises about 50 to 90 g/ft³ of platinum and 100 to 225 g/ft³ ofpalladium. The preferred refractory oxide support is a metal oxiderefractory which is preferably selected from ceria, silica, zirconia,alumina, titania and mixtures thereof with alumina and titania beingmost preferred. The preferred titania is characterized by as recitedabove with titania sol most preferred. The preferred catalyst isreduced. Testing on a coated automotive radiator resulted in conversionsof a low molecular weight mono-olefin such as propylene to water andcarbon dioxide with 1.5 to 4 wt. % of platinum on an alumina or titaniasupport have been between 15 and 25% where the propylene concentrationwas about 10 parts per million propylene and the space velocity wasabout 320,000 reciprocal hours. These catalysts were not reduced.Reduction of the catalyst improves conversion.

Catalysts useful for the oxidation of both carbon monoxide andhydrocarbons generally include those recited above as useful to treateither carbon monoxide or hydrocarbons. Most preferred catalysts whichhave been found to have good activity for the treatment of both carbonmonoxide and hydrocarbon such as unsaturated olefins comprise platinumcomponent supported on a preferred titania support. The compositionpreferably comprises a binder and can be coated on a suitable supportstructure in amounts of from 0.8 to 1.0 g/in. A preferred platinumconcentration ranges from 2 to 6% and preferably 3 to 5% by weight ofplatinum metal on the titania support. Useful and preferred substratecell densities are equivalent to about 300 to 400 cells per square inch.The catalyst is preferably reduced as a powder or on the coated articleusing a suitable reducing agent. Preferably the catalyst is reduced inthe gas stream comprising about 7% hydrogen with the balance nitrogen atfrom 200° to 500° C. or from 1 to 12 hours. The most preferred reductionor forming temperature is 400° C. for 2-6 hours. This catalyst has beenfound to maintain high activity in air and humidified air at elevatedtemperatures of up to 100° C. after prolonged exposure.

Useful catalysts which can treat both ozone and carbon monoxide compriseat least one precious metal component, most preferably a precious metalselected from palladium, platinum and mixtures thereof on a suitablesupport such as a refractory oxide support. A combination of a platinumcomponent and a palladium component results in improved CO conversion atan increase in cost and is most preferred where greater conversion isdesired and cost increase is acceptable. Useful refractory oxidesupports comprise ceria, zirconia, alumina, titania, silica and mixturesthereof including a mixture of zirconia and silica as recited above.Also useful and preferred as a support are the above describedcoprecipitates of manganese oxides and zirconia. The compositioncomprises from 0.1 to 20.0, preferably 0.5 to 15, and more preferablyfrom 1 to 10 weight percent of the precious metal component on thesupport based on the weight of the precious metal and the support.Palladium is preferably used in amounts from 2 to 15 and more preferablyfrom 3 to 8 weight percent. Platinum is preferably used in amounts offrom 0.1 to 6 percent and more preferably 2 to 5 weight percent. Apreferred composition is a composition wherein the refractory componentcomprises ceria and the precious metal component comprises palladium.This composition has resulted in relatively high ozone and carbonmonoxide conversions. More particularly, testing of this composition ona coated radiator has resulted in a 21% conversion of carbon monoxide inan air stream comprising 16 ppm of carbon monoxide contacting a surfaceat 95° C. with a face velocity of the gas stream being 5 miles per hour.The same catalyst resulted in a 55% ozone conversion where the streamcontained 0.25 ppm of ozone and the treating surface was at 25° C. withan air stream face velocity of 10 miles per hour. Also preferred is acomposition comprising a precious metal, preferably a platinum groupmetal, more preferably selected from platinum and palladium components,and most preferably a platinum component and the above recitedcoprecipitate of manganese oxide and zirconia. This above recitedprecious metal containing catalyst in the form of a catalyst powder orcoating on a suitable substrate is in reduced form. Preferred reductionconditions include those recited above with the most preferred conditionbeing from 250° to 350° C. for from 2 to 4 hours in a reducing gascomprising 7% hydrogen and 93% nitrogen. This catalyst has been found tobe particularly useful in treating both carbon monoxide and ozone. Otheruseful compositions to convert ozone to oxygen and carbon monoxide tocarbon dioxide comprise a platinum component supported on carbon,manganese dioxide, or a refractory oxide support, and optionally havingan additional manganese component.

A useful and preferred catalyst which can treat ozone, carbon monoxideand hydrocarbons, as well as partially oxygenated hydrocarbons,comprises a precious metal component, preferably a platinum component ona suitable support such as a refractory oxide support. A combination ofa platinum component and a palladium component results in improved COconversion at an increase in cost and is most preferred where greaterconversion is desired and cost increase is acceptable. Useful refractoryoxide supports comprise ceria, zirconia, alumina, titania, silica andmixtures thereof including a mixture of zirconia and silica as recitedabove. Also useful is a support including the above-recitedcoprecipitate of manganese oxide and zirconia. The composition comprisesfrom 0.1 to 20, preferably 0.5 to 15 and more preferably 1 to 10 wt. %of the precious metal component on the refractory support based on theweight of the precious metal and the support. Where the hydrocarboncomponent is sought to be converted to carbon dioxide and water,platinum is the most preferred catalyst and is preferably used inamounts of from 0.1 to 5% and more preferably 2 to 5% by weight.

In specific embodiments, there can be a combination of catalystsincluding the above recited catalyst as well as a catalyst which isparticularly preferred for the treatment of ozone such as a catalystcomprising a manganese component. The manganese component can beoptionally combined with a platinum component. The manganese andplatinum can be on the same or different supports. There can be up to80, preferably up to 50, more preferably from 1 to 40 and yet morepreferably from 10 to 35 wt. % of the manganese component based on theweight of the precious metal and manganese in the pollutant treatingcomposition. The catalyst loading is the same at that recited above withregard to the ozone catalyst. A preferred composition is a compositionwherein the refractory component comprises an alumina or titania supportand the precious metal component comprises a platinum component. Testingof such a composition coated onto a radiator has resulted in 68 to 72%conversion of carbon monoxide, 8 to 15% conversion of ozone and 17 to18% conversion of propylene when contacting a surface at 95° C. with aface velocity of the gas stream being about ten miles per hour (hourlyspace velocity of 320,000 per reciprocal hours) with air dew point at35° F. Generally, as the contacting surface temperature decreases andthe space velocity or face velocity of the atmosphere air flow over thepollutant contacting surface increases, the percent conversiondecreases.

Catalyst activity, particularly to treat carbon monoxide andhydrocarbons can be further enhanced by reducing the catalyst in aforming gas such as hydrogen, carbon monoxide, methane or hydrocarbonplus nitrogen gas. Alternatively, the reducing agent can be in the formof a liquid such as a hydrazine, formic acid, and formate salts such assodium formate solution. The catalyst can be reduced as a powder orafter coating onto a substrate. The reduction can be conducted in gas atfrom 150°-500° C., preferably 200°-400° C. for 1 to 12 hours, preferably2 to 8 hours. In a preferred process, coated article or powder can bereduced in a gas comprising 7% hydrogen in nitrogen at 275°-350° C. for2 to 4 hours.

An alternate composition for use in the method and apparatus of thepresent invention comprises a catalytically active material selectedfrom the-group consisting of precious metal components includingplatinum group metal components, gold components and silver componentsand a metal component selected from the group consisting of tungstencomponents and rhenium components. The relative amounts of catalyticallyactive material to the tungsten component and/or rhenium component basedon the weight of the metal are from 1 to 25, to 15 to 1.

The composition containing a tungsten component and/or a rheniumcomponent preferably comprises tungsten and/or rhenium in the oxideform. The oxide can be obtained by forming the composition usingtungsten or rhenium salts and the composition can subsequently becalcined to form tungsten and/or rhenium oxide. The composition cancomprise further components such as supports including refractory oxidesupports, manganese components, carbon, and coprecipitates of amanganese oxide and zirconia. Useful refractory metal oxides includealumina, silica, titania, ceria, zirconia, chromia and mixtures thereof.The composition can additionally comprise a binder material, such asmetal sols including alumina or titania sols or polymeric binder whichcan be provided in the form of a polymeric latex binder.

In preferred compositions, there are from 0.5 to 15, preferably 1 to 10,and most preferably from 3 to 5 percent by weight of the catalyticallyactive material. The preferred catalytically active materials areplatinum group metals with platinum and palladium being more preferredand platinum being most preferred. The amount of tungsten and/or rheniumcomponent based on the metals ranges 1 to 25, preferably 2 to 15 andmost preferably 3 to 10 weight percent. The amount of binder can varyfrom 0 to 20 weight percent, preferably 0.5 to 20, more preferably 2 to10 and most preferably 2 to 5 weight percent. Depending on the supportmaterial a binder is not necessary in this composition. Preferredcompositions comprise from 60 to 98.5 weight percent of a refractoryoxide support, from 0.5 to 15 weight percent of the catalytically activematerial, from 1 to 25 weight of the tungsten and/or rhenium component,and from 0 to 10 weight percent binder.

Compositions containing the tungsten component and rhenium component canbe calcined under conditions as recited above. Additionally, thecomposition can be reduced. However, as shown in the examples below, thecompositions need not be reduced and the presence of the tungsten and/orrhenium component can result in conversions of carbon monoxide andhydrocarbons comparable to compositions containing platinum group metalswhich have been reduced.

The pollutant treating compositions of the present invention preferablycomprise a binder which acts to adhere the composition and to provideadhesion to the atmosphere contacting surface. It has been found that apreferred binder is a polymeric binder used in amounts of from 0.5 to20, more preferably 2 to 10, and most preferably to 2 to 5 percent byweight of binder based on the weight of the composition. Preferably, thebinder is a polymeric binder which can be a thermosetting orthermoplastic polymeric binder. The polymeric binder can have suitablestabilizers and age resistors known in the polymeric art. The polymercan be a plastic or elastomeric polymer. Most preferred arethermosetting, elastomeric polymers introduced as a latex into thecatalyst into a slurry of the catalyst composition, preferably anaqueous slurry. Upon application of the composition and heating thebinder material can crosslink providing a suitable support whichenhances the integrity of the coating, its adhesion to the atmospherecontacting surface and provides structural stability under vibrationsencountered in motor vehicles. The use of preferred polymeric binderenables the pollutant treating composition to adhere to the atmospherecontacting surface without the necessity of an undercoat layer. Thebinder can comprise water resistant additives to improve waterresistance and improve adhesion. Such additives can include fluorocarbonemulsions and petroleum wax emulsions.

Useful polymeric compositions include polyethylene, polypropylene,polyolefin copolymers, polyisoprene, polybutadiene, polybutadienecopolymers, chlorinated rubber, nitrile rubber, polychloroprene,ethylene-propylene-diene elastomers, polystyrene, polyacrylate,polymethacrylate, polyacrylonitrile, poly(vinyl esters), poly(vinylhalides), polyamides, cellulosic polymers, polyimides, acrylics, vinylacrylics and styrene acrylics, poly vinyl alcohol, thermoplasticpolyesters, thermosetting polyesters, poly(phenylene oxide),poly(phenylene sulfide), fluorinated polymers such aspoly(tetrafluoroethylene) polyvinylidene fluoride, poly(vinylfluoride)and chloro/fluoro copolymers such as ethylene chlorotrifluoroethylenecopolymer, polyamide, phenolic resins and epoxy resins, polyurethane,and silicone polymers. A most preferred polymeric material is an acrylicpolymeric latex as described in the accompanying examples.

Particularly preferred polymers and copolymers are vinyl acrylicpolymers and ethylene vinyl acetate copolymers. A preferred vinylacrylic polymer is a cross linking polymer sold by National Starch andChemical Company as Xlink 2833. It is described as a vinyl acrylicpolymer having a Tg of −15° C., 45% solids, a pH of 4.5 and a viscosityof 300 cps. In particular, it is indicated to have vinyl acetate CAS No.108-05-4 in a concentration range of less than 0.5 percent. It isindicated to be a vinyl acetate copolymer. Other preferred vinyl acetatecopolymers which are sold by the National Starch and Chemical Companyinclude Dur-O-Set E-623 and Dur-O-Set E-646. Dur-O-Set E-623 isindicated to be ethylene vinyl acetate copolymers having a Tg of 0° C.,52% solids, a pH of 5.5 and a viscosity of 200 cps. Dur-O-Set E-646 isindicated to be an ethylene vinyl acetate copolymer with a Tg of −12°C., 52% solids, a pH of 5.5 and a viscosity of 300 cps. A useful andpreferred binder is a crosslinking acrylic copolymer sold by NationalStarch and Chemical Company as X-4280. It is described as a milk whiteaqueous emulsion having a pH of 2.6; a boiling point of 212° F., afreezing point of 32° F.; a specific gravity of 1.060; a viscosity of100 cps. An alternate and useful binding material is the use of azirconium compound. Zirconyl acetate is preferred zirconium compoundused. It is believed that zirconia acts as a high temperaturestabilizer, promotes catalytic activity, and improves catalyst adhesion.Upon calcination, zirconium compounds such as zirconyl acetate areconverted to ZrO₂ which is believed to be the binding material. Varioususeful zirconium compounds include acetates, hydroxides, nitrates, etc.for generating ZrO₂ in catalysts. In the case of using zirconyl acetateas a binder for the present catalysts, ZrO₂ will not be formed unlessthe radiator coating is calcined. Since good adhesion has been attainedat a “calcination” temperature of only 120° C., it is believed that thezirconyl acetate has not decomposed to zirconium oxide but instead hasformed a cross linked network with the pollutant treating material suchas CARULITE® catalyst particles and the acetates which were formed fromball milling with acetic acid. Accordingly, the use of any zirconiumcontaining compounds in the present catalysts are not restricted only tozirconia. Additionally, the zirconium compounds can be used with otherbinders such as the polymeric binder recited above.

An alternate pollutant treating catalyst composition can compriseactivated carbon composition. The carbon composition comprises activatedcarbon, a binder, such as a polymeric binder, and optionallyconventional additives such as defoamers and the like. A usefulactivated carbon composition comprises from 75 to 85 weight percentactivated carbon such as “coconut shell” carbon or carbon from wood anda binder such as an acrylic binder with a defoamer. Useful slurriescomprise from 10 to 50 weight percent solids. The activated carbon cancatalyze reduction of ozone to oxygen, as well as adsorb otherpollutants.

Pollutant treating catalyst compositions of the present invention can beprepared in any suitable process. A preferred process is disclosed inU.S. Pat. No. 4,134,860 herein incorporated by reference. In accordancewith this method, the refractory oxide support such as activatedalumina, titania or activated silica alumina is jet milled, impregnatedwith a catalytic metal salt, preferably precious metal salt solution andcalcined at a suitable temperature, typically from about 300° C. toabout 600° C., preferably from about 350° C. to about 550° C., and morepreferably from about 400° C. to about 500° C. for from about 0.5 toabout 12 hours. Palladium salts are preferably a palladium nitrate or apalladium amine such as palladium tetraamine acetate, or palladiumtetraamine hydroxide. Platinum salts preferably include platinumhydroxide solubilized in an amine. In specific and preferred embodimentsthe calcined catalyst is reduced as recited above.

In an ozone treating composition, a manganese salt, such as manganesenitrate, can then be mixed with the dried and calcined alumina supportedpalladium in the presence of deionized water. The amount of water addedshould be an amount up to the point of incipient wetness. Reference ismade to the method reviewed in the above referenced and incorporatedU.S. Pat. No. 4,134,860. The point of incipient wetness is the point atwhich the amount of liquid added is the lowest concentration at whichthe powdered mixture is sufficiently dry so as to absorb essentially allof the liquid. In this way a soluble manganese salt such as Mn(NO₃)₂ inwater can be added into the calcined supported catalytic precious metal.The mixture is then dried and calcined at a suitable temperature,preferably 400 to 500° C. for about 0.5 to about 12 hours.

Alternatively, the supported catalytic powder (i.e., palladium supportedon alumina) can be combined with a liquid, preferably water, to form aslurry to which a solution of a manganese salt, such as Mn(NO₃)₂ isadded. Preferably, the manganese component and palladium supported on arefractory support such as activated alumina, more preferably activatedsilica-alumina is mixed with a suitable amount of water to result in aslurry having from 15 to 40% and preferable 20 to 35 weight percentsolids. The combined mixture can be coated onto a carrier such as aradiator and the radiator dried in air at suitable conditions such as50° C. to 150° C. for 1 to 12 hours. The substrate which supports thecoating can then be heated in an oven at suitable conditions typicallyfrom 300° C. to 550° C., preferably 350° C. to 500° C., more preferably350° C. to 450° C. and most preferably from 400° C. and 500° C. in anoxygen containing atmosphere, preferably air for about 0.5 to about 12hours to calcine the components and help to secure the coating to thesubstrate atmosphere contacting surface. Where the composition furthercomprises a precious metal component, it is preferably reduced aftercalcining.

A method of the present invention includes forming a mixture comprisinga catalytically active material selected from at least one platinumgroup metal component, a gold component, a silver component, a manganesecomponent and mixtures thereof and water. The catalytically activematerial can be on a suitable support, preferably a refractory oxidesupport. The mixture can be milled, and then optionally be calcined andreduced when using precious metal catalytic material. The calcining stepcan be conducted prior to milling and adding the polymeric binder. It isalso preferred to reduce the catalytically active material prior tomilling, calcining and adding the polymeric binder. The slurry comprisesa carboxylic acid compound or polymer containing carboxylic acid groupsor derivatives thereof in an amount to result in a pH of about from 3 to7, typically 3 to 6. Preferably the acid comprises from 0.5 to 15 weightpercent of glacial acetic acid based on the weight of the catalyticallyactive material and acetic acid. The amount of water can be added assuited to attain a slurry of the desired solids concentration and/orviscosity. The percent solids are typically 20 to 50 and preferably 30to 40 percent by weight. The preferred vehicle is deionized water(D.I.). The acetic acid can be added upon forming the mixture of thecatalytically active material, which may have been calcined, with water.Alternatively, the acetic acid can be added with the polymeric binder. Apreferred composition to treat ozone using manganese dioxide as thecatalyst can be made using about 1,500 g of manganese dioxide which ismixed with 2,250 g of deionized water and 75 g of acetic acid. Themixture is combined in a 1 gallon ballmill and ballmilled for about 4hours until approximately 90% of the particles are less than 8micrometers. The ballmill is drained and 150 g of polymeric binder isadded. The mixture is then blended on a rollmill for 30 minutes. Theresulting mixture is ready for coating onto a suitable substrate such asan automobile radiator according to the methods described below.

It has been found that compatibility of the components of a slurrycomprising a catalytic material and a polymeric binder, such as a latexemulsion, is desirable to maintain slurry stability and uniformity. Forthe purpose of the present invention compatibility means that the binderand the catalytic material remain as a mixture of separate particles inthe slurry. It is believed that where the polymeric binder is a latexemulsion and the catalytic material have electrical charges which causethem to repel each other, they are compatible and the slurry is stableand has a uniform distribution of the catalytic material and the polymerlatex in the liquid vehicle, e.g. aqueous fluid such as water. If thecatalytic material and latex emulsion particles do not mutually repeleach other, irreversible agglomeration of the latex on the catalyticmaterial will occur. These materials are therefore incompatible and thelatex comes out of the emulsion.

Compatibility of a high surface area catalyst with the organic latexbinder is a key property in preparing a stable, uniform slurry. If thecatalyst and latex emulsion particles do not mutually repel each other,irreversible agglomeration will occur. The result of this will be anunstable, non-uniform slurry which will produce a poorly adherentcoating. Although the mutual repulsion of the catalyst and binderparticles is controlled by a variety physical factors, surface chargeplays a key role. Since latex emulsion particles are typicallynegatively charged, catalyst particles must be similarly charged. Zetapotential measurements have shown, however, that catalyst particles,such as MnO₂ are only slightly negatively or even positively charged,and as a result, irreversible coagulation of the catalyst and latexoccurs (i.e. catalyst and latex are not compatible) . It has been foundthat although the above described method of adding acetic acid providescertain advantages to the slurries of the present invention, such asviscosity control, it does not enhance compatibility and may even bedetrimental to aged slurry stability.

Where the catalytically material is positively or slightly negativelycharged, improved compatibility can be achieved by making the slurrymore basic. The pH of the slurry can be controlled depending on theacidity of the catalytic material, with preferred pH levels being atleast 6, preferably at least 7, more preferably at least 8.5. Generally,the slurry should not be too caustic and a preferred upper limit isabout 11. A preferred range is from 8.5 to 11.

Maintaining a pH≧8.5 of a slurry comprising a latex emulsion and MnO₂(cryptomelane) is critical. If the pH drops below 8.5 for an extendedperiod of time (days), the binder and catalyst will irreversiblycoagulate. Despite the large negative charge on the cryptomelaneparticles at this pH, long term stability of cryptomelane containingslurries has been difficult to achieve. Preferred binders arepoly(acrylic) acid derivative based binders with a particularlypreferred binder which has long term stability under these conditionsbeing an acrylic latex sold by National Starch as x-4280 acrylic latex.The difficulty in achieving long term compatibility even with basicslurries containing negatively charged latex and catalyst particlesindicates that although surface charge is important, it is not the onlyfactor in determining binder/catalyst compatibility. Other factors whichplay a role include emulsion particle size, surfactant package, etc. Thepresent method involves raising the pH of the ball milled catalystslurry to pH≧8.5 and preferably 9 to enhance stability. An alternativemethod to enhance slurry stability involves adding a surfactant such asa polymeric dispersant to the slurry instead of or in addition toincreasing the pH. In the second case, binder/catalyst compatibility isachieved by adding a polymeric acrylate derived dispersant (ca. 3%solids basis) instead of increasing the pH. The result is the same,however, in that the catalyst particle is given a large negative chargewhich can repel the like charged latex particles. The dispersant can beadded during the ball milling operation or after. Despite generating alarge negative charge on the catalyst particles, not all dispersantswork equally as well. Preferred dispersants comprise polymers containingcarboxylic acid groups or derivatives thereof such as esters and salts.Preferred dispersants include Accusol 445 (from Rohm & Haas) and Colloid226/35 (from Rhone-Poulenc). Useful dispersants and a review ofdispersion technology are presented in, Additives for DispersionTechnology, published by Rhone-Poulenc, Surfactants & Specialties herebyincorporated by reference. Useful polymeric dispersants include but arenot limited to polyacrylic acid partial sodium salts and anioniccopolymer sodium salts sold by Rhone-Poulenc as Colloid™ polymericdispersants. Again, although surface charge is an important factor indetermining catalyst/binder compatibility, it is not the only factor. Ingeneral, the dispersant (particularly Colloid 226) does a good job ofstabilizing the slurry since a greater variety of latex binders (e.g.acrylics, styrene acrylics, and EVA's) are compatible. Long termcompatibility problems may be addressed by increasing the quantity ofdispersant, raising the pH somewhat, or both.

The above recited methods enhance compatibility and result in a stablecatalyst slurry. Both methods generate a large negative surface chargeon the catalyst particle which in turn stabilizes the catalyst in thepresence of the like charged (anionic) latex emulsion particles. Forboth systems, good adhesion has been observed (i.e. catalyst cannot bewiped off the face of a coated monolith) with a 10% by weight loading(solids basis) of the polymeric binder. At 5%, adhesion is not as good,so the optimum loading is probably somewhere in between.

While these methods have been shown to enhance compatability ofMnO₂/latex slurries, the present invention is not limited to systemsusing negatively charged latex emulsions. Those skilled in the art willunderstand that slurry compatability can likewise be achieved usingcationic latex emulsions, using cationic surfactant and/or dispersantpackages to stabilize the catalyst particles.

The polymeric slurries of the present, particularly polymer latexslurries, can contain conventional additives such as thickeners,biocides, antioxidants and the like.

The pollutant treating composition can be applied to the atmospherecontacting vehicle surface by any suitable means such as spray coating,powder coating, or brushing or dipping the surface into a catalystslurry.

The atmosphere contacting surface is preferably cleaned to removesurface dirt, particularly oils which could result in poor adhesion ofthe pollutant treating composition to the surface. Where possible, it ispreferred to heat the substrate on which the surface is located to ahigh enough temperature to volatilize or burn off surface debris andoils.

Where the substrate on which there is an atmosphere contacting surfaceis made of a material which can withstand elevated temperatures such asan aluminum radiator, the substrate surface can be treated in such amanner as to improve adhesion to the catalyst composition, preferablythe ozone carbon monoxide, and/or hydrocarbon catalyst composition. Onemethod is to heat the aluminum substrate such as the radiator to asufficient temperature in air for a sufficient time to form a thin layerof aluminum oxide on the surface. This helps clean the surface byremoving oils which may be detrimental to adhesion. Additionally, if thesurface is aluminum a sufficient layer of oxidized aluminum has beenfound to be able to be formed by heating the radiator in air for from0.5 to 24 hours, preferably from 8 to 24 hours and more preferably from12 to 20 hours at from 350° C. to 500° C., preferably from 400 to 500°C. and more preferably 425 to 475° C. In some cases, sufficient adhesionwithout the use of an undercoat layer has been attained where analuminum radiator has been heated at 450° C. for 16 hours in air. Thismethod is particularly useful when applying the coating to new surfacessuch as radiators or air conditioner condensers prior to assembly in amotor vehicle either as original equipment or replacement.

Adhesion may improve by applying an undercoat or precoat to thesubstrate. Useful undercoats or precoats include refractory oxidesupports of the type discussed above, with alumina preferred. Apreferred undercoat to increase adhesion between the atmospherecontacting surface and an overcoat of an ozone catalyst composition isdescribed in commonly assigned U.S. Pat. No. 5,422,331 hereinincorporated herein by reference. The undercoat layer is disclosed ascomprising a mixture of fine particulate refractory metal oxide and asol selected from silica, alumina, zirconia and titania sols. Inaccordance with the method of the present invention, surfaces onexisting vehicles can be coated while the substrate such as theradiator, radiator fan or air conditioner condenser is located on thevehicle. The catalyst composition can be applied directly to thesurface. Where additional adhesion is desired, an undercoat can be usedas recited above.

Where it is practical to separate the radiator from the vehicle, asupport material such as activated alumina, silica-alumina, bulktitania, titanium sol, silica zirconia, manganese zirconia and others asrecited can be formed into a slurry and coated on the substratepreferably with a silica sol to improve adhesion. The precoatedsubstrate can subsequently be coated with soluble precious metal saltssuch as the platinum and/or palladium salts, and optionally manganesenitrate. The coated substrate can then be heated in an oven in air forsufficient time (0.5 to 12 hours at 350° C. to 550° C.) to calcine thepalladium and manganese components to form the oxides thereof.

The present invention can comprise adsorption compositions supported onthe atmosphere contacting surface. The adsorption compositions can beused to adsorb gaseous pollutants such as hydrocarbons and sulfurdioxide as well as particulate matter such as particulate hydrocarbon,soot, pollen, bacteria and germs. Useful supported compositions caninclude adsorbents such as zeolite to adsorb hydrocarbons. Usefulzeolitic compositions are described in Publication No. WO 94/27709published Dec. 8, 1994 and entitled Nitrous Oxide Decomposition Catalysthereby incorporated by reference. Particularly preferred zeolites areBeta zeolite, and dealuminated Zeolite Y.

Carbon, preferably activated carbon, can be formed into carbonadsorption compositions comprising activated carbon and binders such aspolymers as known in the art. The carbon adsorption composition can beapplied to the atmosphere contacting surface. Activated carbon canadsorb hydrocarbons, volatile organic components, bacteria, pollen andthe like. Yet another adsorption composition can include componentswhich can adsorb SO₃. A particularly useful SO₃ adsorbent is calciumoxide. The calcium oxide is converted to calcium sulfate. The calciumoxide adsorbent compositions can also contain a vanadium or platinumcatalyst which can be used to convert sulfur dioxide to sulfur trioxidewhich can then be adsorbed onto the calcium oxide to form calciumsulfate.

In addition to treatment of atmospheric air containing pollutants atambient condition or ambient operating conditions, the present inventioncontemplates the catalytic oxidation and/or reduction of hydrocarbons,nitrogen oxides and residual carbon monoxide using conventional threeway catalysts supported on electrically heated catalysts such as areknown in the art. The electrically heated catalysts can be located onelectrically heated catalyst monolith 56 illustrated in FIG. 1. Suchelectrically heated catalyst substrates are known in the art and aredisclosed in references such as U.S. Pat. Nos. 5,308,591 and 5,317,869hereby incorporated by reference. For the purposes of the presentinvention, the electrically heated catalyst is a metal honeycomb havinga suitable thickness to fit in the flow direction, preferably of from ⅛inch to 12 inches, and more preferably 0.5 to 3 inches. Where theelectrically heated catalyst must fit into a narrow space, it can befrom 0.25 to 1.5 inches thick. Preferred supports are monolithiccarriers of the type having a plurality of fine, parallel gas flowpassages extending therethrough from an inlet face to an outlet face ofthe carrier so that the passages are open to air flow entering from thefront 26 and passing through the monolith 56 in the direction toward thefan 20. Preferably the passages are essentially straight from theirinlet to their outlet and are defined by walls in which the catalyticmaterial is coated as a wash coat so that the gases flowing through thepassages contact the catalytic material. The flow passages of themonolithic carrier are thin wall channels which can be of any suitablecross-sectional shape and size such as trapezoidal, rectangular, square,sinusoidal, hexagonal, oval, circular or formed from metallic componentswhich are corrugated and flat as are known in the art. Such structuresmay contain from about 60 to 600 or more gas inlet openings (“cells”)per square inch of cross section. The monolith may be made of anysuitable material and is preferably capable of being heated uponapplication of an electric current. A useful catalyst to apply is thethree way catalyst (TWC) as recited above which can enhance theoxidation of hydrocarbons and carbon monoxide as well as the reductionof nitrogen oxides. Useful TWC catalysts are recited in U.S. Pat. Nos.4,714,694; 4,738,947; 5,010,051; 5,057,483; and 5,139,992.

The present invention is illustrated further by the following exampleswhich are not intended to limit the scope of this invention.

EXAMPLES Example 1

A 1993 Nissan Altima radiator core (Nissan part number 21460-1E400) washeat treated in air to 450° C. for 16 hours to clean and oxidize thesurface and then a portion coated with high surface area silica-aluminaundercoat (dry loading=0.23 g/in³) by pouring a water slurry containingthe silica-alumina through the radiator channels, blowing out the excesswith an air gun, drying at room temperature with a fan, and thencalcining to 450° C. The silica-alumina slurry was prepared by ballmilling high surface area calcined SRS-II alumina (Davison) with aceticacid (0.5% based on alumina) and water (total solids ca. 20%) to aparticle size of 90% <4 μm. The ball milled material was then blendedwith Nalco silica sol (#91SJ06S—28% solids) in a ratio of 25%/75%. TheSRS-II alumina is specified to have a structure of xSiO₂.yAl₂O₃.zH₂Owith 92-95% by weight Al₂O₃ and 4-7% by weight SiO₂ after activation.BET surface area is specified to be a minimum of 260 m²/g aftercalcination.

A Pd/Mn/Al₂O₃ catalyst slurry (nominally 10% by weight palladium onalumina) was prepared by impregnating high surface area SRS-II alumina(Davison) to the point of incipient wetness with a water solutioncontaining sufficient palladium tetraamine acetate. The resulting powderwas dried and then calcined for 1 hour at 450° C. The powder wassubsequently mixed under high shear with a water solution of manganesenitrate (amount equivalent to 5.5% by weight MnO₂ on the alumina powder)and sufficient dilution water to yield a slurry of 32-34% solids. Theradiator was coated with the slurry, dried in air using a fan, and thencalcined in air at 450° C. for 16 hours. This ozone destruction catalystcontained palladium (dry loading=263 g/ft³ of radiator volume) andmanganese dioxide (dry loading=142 g/ft³) on high surface area SRS-IIalumina. The partially coated radiator reassembled with the coolanttanks, also referred to as headers is shown in FIG. 8.

Ozone destruction performance of the coated catalyst was determined byblowing an air stream containing a given concentration of ozone throughthe radiator channels at face velocities typical of driving speeds andthen measuring the concentration of ozone exiting the back face of theradiator. The air used was at about 20° C. and had a dew point of about35° F. Coolant fluid was circulated through the radiator at atemperature of about 50° C. Ozone concentrations ranged from 0.1-0.4ppm. Ozone conversion was measured at linear air velocities (facevelocities) equivalent to 12.5 miles per hour to be 43%; at 25 mph to be33%; at 37.5 mph to be 30% and at 49 mph to be 24%.

Example 2 (Comparative)

A portion of the same radiator used in Example 1 which was not coatedwith catalyst was similarly evaluated for ozone destruction performance(i.e. control experiment). No conversion of ozone was observed.

Example 3

After heat treatment for 60 hours in air at 450° C., a Lincoln Town Carradiator core (part #F1VY-8005-A) was coated sequentially in 6″×6″square patches with a variety of different ozone destruction catalystcompositions (i.e., different catalysts; catalyst loadings, binderformulations, and heat treatments). Several of the radiator patches wereprecoated with a high surface area alumina or silica-alumina andcalcined to 450° C. prior to coating with the catalyst. The actualcoating was accomplished similarly to Example 1 by pouring a waterslurry containing the specific catalyst formulation through the radiatorchannels, blowing out the excess with an air gun, and drying at roomtemperature with a fan. The radiator core was then dried to 120° C., ordried to 120° C. and then calcined to 400 to 450° C. The radiator corewas then reattached to its plastic tanks and ozone destructionperformance of the various catalysts was determined at a radiatorsurface temperature of about 40° C. to 50° C. and a face velocity of 10mph as described in Example 1.

Table I summarizes the variety of catalysts coated onto the radiator.Details of the catalyst slurry preparations are given below.

A Pt/Al₂O₃ catalyst (nominally 2% by weight Pt on Al₂O₃) was prepared byimpregnating 114 g of a platinum salt solution derived from H₂Pt(OH)₆solubilized in an amine, (17.9% Pt), dissolved in 520 g of water to 1000g of Condea SBA-150 high surface area (specified to be about 150 m²/g)alumina powder. Subsequently 49.5 g of acetic acid was added. The powderwas then dried at 110° C. for 1 hour and calcined at 550° C. for 2hours. A catalyst slurry was then prepared by adding 875 g of the powderto 1069 g of water and 44.6 g of acetic acid in a ball mill and millingthe mixture to a particle size 90%<10 μm. (Patches 1 and 4)

A carbon catalyst slurry was a formulation (29% solids) purchased fromGrant Industries, Inc., Elmwood Park, N.J. The carbon is derived fromcoconut shell. There is an acrylic binder and a defoamer. (Patches 8 and12)

The CARULITE® 200 catalyst (CuO/MnO₂) was prepared by first ball milling1000 g of CARULITE® 200 catalyst (purchased from Carus Chemical Co.,Chicago, Ill.) with 1500 g of water to a particle size 90%<6 μm.CARULITE® 200 catalyst is specified as containing 60 to 75 weightpercent MnO₂, 11-14 percent CuO and 15-16 percent Al₂O₃. The resultingslurry was diluted to ca. 28% solids and then mixed with either 3%(solids basis) of Nalco #1056 silica sol or 2% (solids basis) NationalStarch #x4260 acrylic copolymer. (Patches 5, 9 and 10)

The Pd/Mn/Al₂O₃ catalyst slurry (nominally 10% by weight palladium onalumina) was prepared as described in Example 1. (Patches 2, 3 and 6)

An I.W. (incipient wetness) Pd/Mn/Al₂O₃ catalyst (nominally 8% palladiumand 5.5% MnO₂ based on alumina) was prepared similarly by firstimpregnating high surface area SRS-II alumina (Davison) to the point ofincipient wetness with a water solution containing palladium tetraamineacetate. After drying and then calcining the powder for two hours at450° C., the powder was reimpregnated to the point of incipient wetnesswith a water solution containing manganese nitrate. Again, after dryingand calcination at 450° C. for two hours, the powder was mixed in a ballmill with acetic acid (3% by weight of catalyst powder) and enough waterto create a slurry of 35% solids. The mixture was then milled until theparticle size was 90%<8 μm. (Patches 7 and 11)

The SiO₂/Al₂O₃ precoat slurry was prepared as described in Example 1.(Patches 3 and 11)

The Al₂O₃ precoat slurry was prepared by ball milling high surface areaCondea SBA-150 alumina with acetic acid (5% by weight based on alumina)and water (total solids ca. 44%) to a particle size of 90%<10 μm.(Patches 9 and 12)

Results are summarized in Table I. The conversion of carbon monoxideafter being on the automobile for 5,000 miles was also measured at theconditions recited in Example 1 for patch #4. At a radiator temperatureof 50° C. and a linear velocity of 10 mph no conversion was observed.

TABLE I CATALYST SUMMARY OZONE PATCH # CATALYST CONVERSION (%) 1Pt/Al₂O₃ 12 0.67 g/in³ (23 g/ft³ Pt) No Precoat No Calcine (120° C.only) 2 Pd/Mn/Al₂O₃ 25 0.97 g/in³ (171 g/ft³ Pd) No Precoat Calcined450° C. 3 Pd/Mn/Al₂O₃ 24 1.19 g/in³ (209 g/ft³ Pd) SiO₂/Al₂O₃ Precoat(0.16 g/in³) Calcined 450° C. 4 Pt/Al₂O₃ 8 0.79 g/in³ (27 g/ft³ Pt) NoPrecoat Calcined 450° C. 5 CARULITE ® 200 Catalyst 50 0.49 g/in³ 3%SiO₂/Al₂O₃ Binder No Precoat Calcined 400° C. 6 Pd/Mn/Al₂O₃ 28 0.39g/in³ (70 g/ft³ Pd) No Precoat Calcined 450° C. 7 I.W. Pd/Mn/Al₂O₃ 500.69 g/in³ (95 g/ft³ Pd) No Precoat No Calcine (120° C. only) 8 Carbon22 0.80 g/in³ No Precoat No Calcine (120° C. only) 9 CARULITE ® 200Catalyst 38 0.65 g/in³ 3% SiO₂/Al₂O₃ Binder Al₂O₃ Precoat (0.25 g/in³)Calcined 450° C. 10 CARULITE ® 200 Catalyst 42 0.70 g/in³ 2% LatexBinder No Precoat No Calcine (120° C. only) 11 I.W. Pd/Mn/Al₂O₃ 46 0.59g/in³ (82 g/ft³ Pd) SiO₂/Al₂O₃ precoat (0.59 g/in³) No Calcine eitherCoat (120° C. only) 12 Carbon 17 1.07 g/in³ Al₂O₃ Precoat (0.52 g/in³)calcined to 450° C. Topcoat not calcined (120° C. only)

Example 4

A 1993 Nissan Altima radiator core (Nissan part number 21460-1E400) washeat treated in air to 400° C. for 16 hours and then a portion coatedwith Condea high surface area SBA-150 alumina (dry loading=0.86 g/in³)by pouring a water slurry containing the alumina through the radiatorchannels, blowing out the excess with an air gun, drying at roomtemperature with a fan, and then calcining to 400° C. The aluminaprecoat slurry was prepared as described in Example 3. The radiator wasthen coated sequentially in 2″×2″ square patches with seven different COdestruction catalysts (Table II). Each coating was applied by pouring awater slurry containing the specific catalyst formulation through theradiator channels, blowing out the excess with an air gun, and drying atroom temperature with a fan.

The CARULITE® catalyst and 2% Pt/Al₂O₃ catalysts (Patch #4 and #6,respectively) were prepared according to the procedure described inExample 3. The 3% Pt/ZrO₂/SiO₂ catalyst (Patch #3) was made by firstcalcining 510 g of zirconia/silica frit (95% ZrO₂/5%SiO₂—MagnesiumElektron XZ0678/01) for 1 hour at 500° C. A catalyst slurry was thenprepared by adding to 480 g of deionized water, 468 g of the resultingpowder, 42 g of glacial acetic acid, and 79.2 g of a platinum saltsolution (18.2% Pt) derived from H₂Pt(OH)₆ solubilized with an amine.The resulting mixture was milled on a ball mill for 8 hours to aparticle size of 90% less than 3 μm.

The 3% Pt/TiO₂ catalyst (Patch #7) was prepared by mixing in aconventional blender 500 g of TiO₂ (Degussa P25), 500 g of deionizedwater, 12 g of concentrated ammonium hydroxide, and 82 g of a platinumsalt solution (18.2% Pt) derived from H₂Pt(OH)₆ solubilized with anamine. After blending for 5 minutes to a particle size of 90% less than5 μm, 32.7 g of Nalco 1056 silica sol and sufficient deionized water toreduce the solids content to ca. 22% was added. The resulting mixturewas blended on a roll mill to mix all ingredients.

The 3% Pt/Mn/ZrO₂ catalyst slurry (Patch #5) was prepared by combiningin a ball mill 70 g of manganese/zirconia frit comprising acoprecipitate of 20 weight percent manganese and 80 weight percentzirconium based on metal weight (Magnesium Elektron XZO719/01), 100 g ofdeionized water, 3.5 g of acetic acid and 11.7 g of a platinum saltsolution (18.2% Pt) derived from H₂Pt(OH)₆ solubilized with an amine.The resulting mixture was milled for 16 hours to a particle size 90%less than 10 μm.

The 2% Pt/CeO₂ catalyst (Patch #1) was prepared by impregnating 490 g ofalumina stabilized high surface area ceria (Rhone Poulenc) with 54.9 gof a platinum salt solution (18.2% Pt) derived from H₂Pt(OH)₆solubilized with an amine and dissolved in deionized water (totalvolume—155 mL). The powder was dried at 110° C. for 6 hours and calcinedat 400° C. for 2 hours. A catalyst slurry was then prepared by adding491 g of the powder to 593 g of deionized water in a ball mill and thenmilling the mixture for 2 hours to a particle size of 90% less than 4μm. The 4.6% Pd/CeO₂ catalyst (Patch #2) was prepared similarly viaincipient wetness impregnation using 209.5 g (180 mL) of palladiumtetraamine acetate solution.

After all seven catalysts were applied, the radiator was calcined forabout 16 hours at 400° C. After attaching the radiator core to theplastic tanks, CO destruction performance of the various catalysts weredetermined by blowing an air stream containing CO (ca. 16 ppm) throughthe radiator channels at a 5 mph linear face velocity (315,000/h spacevelocity) and then measuring the concentration of CO exiting the backface of the radiator. The radiator temperature was ca. 95° C., and theair stream had a dew point of approximately 35° F. Results aresummarized in Table II.

Ozone destruction performance was measured as described in Example 1 at25° C., 0.25 ppm ozone, and a linear face velocity of 10 mph with a flowof 135.2 L/min and an hourly space velocity of 640,000/h. The air usedhad a dewpoint of 35° F. Results are summarized in Table II. FIG. 9illustrates CO conversion v. temperature for Patch Nos. 3, 6 and 7.

The catalysts were also tested for the destruction of propylene byblowing an air stream containing propylene (ca. 10 ppm) through theradiator channels at a 5 mph linear face velocity, with a flow rate of68.2 L/min and an hourly space velocity of 320,000/h, and then measuringthe concentration of propylene exiting the back face of the radiator.The radiator temperature was ca. 95° C., and the air stream had a dewpoint of approximately 35° F. Results are summarized in Table II.

TABLE II CO/HC/OZONE CONVERSION SUMMARY CARBON MONOXIDE OZONE PROPYLENEPATCH # CATALYST CONVERSION (%)¹ CONVERSION (%)² CONVERSION (%)³ 1 2%Pt/CeO₂ 2 14 0 0.7 g/in³ (24 g/ft³ Pt) 2 4.6% Pd/CeO₂ 21 55 0 0.5 g/in³(40 g/ft³ Pd) 3 3% Pt/ZrO₂/SiO₂ 67 14 2 0.5 g/in³ (26 g/ft³ Pt) 4CARULITE ® 200 Catalyst 5 56 0 0.5 g/in³ 3% SiO₂/Al₂O₃ binder 5 3%Pt/Mn/ZrO₂ 7 41 0 0.7 g/in³ (36 g/ft³ Pt) 6 2% Pt/Al₂O₃ 72 8 17 0.5g/in³ (17 g/ft³ Pt) 7 3% Pt/TiO₂ 68 15 18 0.7 g/in³ (36 g/ft³ Pt) 3%SiO₂/Al₂O₃ binder ¹Test Conditions: 16 ppm CO; 95° C.; 5 mph facevelocity; 68.2 L/min; LHSV (hourly space velocity) = 320,000/h; Airdewpoint = 35° F. ²Test Conditions: 0.25 ppm O₃; 25° C.; 10 mph facevelocity; 135.2 L/min; LHSV (hourly space velocity) = 640,000/h; Airdewpoint = 35° F. ³Test Conditions: 10 ppm propylene; 95° C.; 5 mph facevelocity; 68.2 L/min; LHSV (hourly space velocity) = 320,000/h; Airdewpoint = 35° F.

Example 5

This example summarizes the technical results from on-the-road vehicletesting conducted in February and March 1995 in the Los Angeles area.The purpose of the test was to measure catalytic ozone decompositionefficiency over a catalyzed radiator under actual driving conditions.The Los Angeles (LA) area was chosen as the most appropriate test siteprimarily due to its measurable ozone levels during this March testingperiod. In addition, specific driving routes are defined in the LA areawhich are typical of AM and PM peak and off-peak driving. Two differentcatalyst compositions were evaluated: 1) CARULITE® 200 catalyst(CuO/MnO₂/Al₂O₃ purchased from Carus Chemical Company); and 2)Pd/Mn/Al₂O₃ (77 g/ft³ Pd) prepared as described in Example 3. Bothcatalysts were coated in patches onto a late model Cadillac V-6 enginealuminum radiator. The radiator was an aluminum replacement for thecopper-brass OEM radiator which was on a Chevrolet Caprice test vehicle.The car was outfitted with ¼″ Teflon® PTFE sampling lines locateddirectly behind each catalyst patch and behind an uncoated portion ofthe radiator (control patch). Ambient (catalyst in) ozone levels weremeasured via a sampling line placed in front of the radiator. Ozoneconcentrations were measured with two Dasibi Model 1003AH ozone monitorslocated in the back seat of the vehicle. Temperature probes were mounted(with epoxy) directly onto each radiator test patch within a few inchesof the sampling line. A single air velocity probe was mounted on thefront face of the radiator midway between the two patches. Data from theozone analyzers, temperature probes, air velocity probe, and vehiclespeedometer were collected with a personal computer located in the trunkand downloaded to floppy disks.

Overall results from the test are summarized in Table III below. Foreach catalyst (CARULITE® catalyst & Pd/Mn/Al₂O₃), results for cold idle,hot idle and on-the-road driving are reported. Data were collected ontwo separate trips to LA in February and March of 1995. The first tripwas cut short after only a few days due to low ambient ozone levels.Although somewhat higher during the second trip in March, ambient levelsstill only averaged approximately 40 ppb. The last three days of testing(March 17-20) had the highest ozone encountered. Peak levels wereapproximately 100 ppb. In general, no trend in conversion vs. ozoneconcentration was noted.

Except for the cold idle results, those reported in Table III areaverages from at least eleven different runs (the actual range of valuesappear in parentheses). Only data corresponding to inlet ozoneconcentration greater or equal to 30 ppb were included. Freeway data wasnot included since ambient levels dropped to 20 ppb or lower. Only tworuns were completed for the cold idle tests. By cold idle refers to datacollected immediately after vehicle startup during idle before thethermostat switches on and pumps warm coolant fluid to the radiator.Overall, ozone conversions were very good for both catalysts with thehighest values obtained during hot idle. This can be attributed to thehigher temperatures and lower face velocities associated with idling.Cold idle gave the lowest conversion due to the lower ambienttemperature of the radiator surface. Driving results were intermediateof hot and cold idle results. Although the radiator was warm,temperature was lower and face velocity higher than those encounteredwith hot idle conditions. In general, ozone conversions measured forCARULITE® catalyst were greater than those measured for Pd/Mn/Al₂O₃(e.g. 78.1 vs. 63.0% while driving). However, for the hot idle anddriving runs, the average temperature of the CARULITE® catalyst wastypically 40° F. greater than the Pd/Mn/Al₂O₃ catalyst while the averageradiator face velocity was typically 1 mph lower.

Overall, the results indicate that ozone can be decomposed at highconversion rates under typical driving conditions.

TABLE III ON-ROAD OZONE CONVERSION RESULTS OZONE CON- TEMPER- FACEVEHICLE VERSION ATURE VELOCITY SPEED (%) (° F.) (mph) (mph) Pd/Mn/Al₂O₃Idle Cold 48.2  70.6 9.0 0.0 (47.2-49.2) (70.5-70.8) (8.9-9.2) Idle Hot80.6 120.0  7.4 0.0 (70.7-89.9) (104.7-145.2) (6.1-8.4) Driving 63.0104.3 13.2  23.3  (55.5-69.9)  (99.2-109.6) (12.2-14.9) (20.5-29.7)CARULITE ® Catalyst (CuO/MnO₂) Idle Cold 67.4  71.8 8.2 0.0 (67.4-67.5)(70.8-72.9) (7.5-8.9) Idle Hot 84.5 157.1 7.5 0.0 (71.4-93.5)(134.8-171.2) (6.7-8.2) Driving 78.1 143.7 12.2  19.2  (72.3-83.8)(132.9-149.6) (11.2-13.5) (13.7-24.8) *Average values. Ranges appear inparentheses.

In general, the results of motor testing are consistent with freshactivity measured in the lab prior to installation of the radiator. Atroom temperature (˜25° C.), 20% relative humidity (0.7% water vaporabsolute), and a 10 mph equivalent face velocity, lab conversions forPd/Mn/Al₂O₃ and CARULITE® catalyst were 55 and 69% respectively.Increasing the RH to 70% at room temperature (˜25° C.) (2.3% water vaporabsolute) lowered conversions to 38 and 52%, respectively. Since thecold idle (70° F.) conversions measured at a 9 mph face velocity were 48and 67% respectively, it would appear that the humidity levelsencountered during the testing were low.

The face velocity of air entering the radiator was low. At an averagedriving speed of roughly 20 mph (typical of local driving), radiatorface velocity was only approximately 13 mph. Even at freeway speeds inexcess of 60 mph, radiator face velocity was only ca. 25 mph. The fansignificantly affects control of air flowing through the radiator. Whileidling, the fan typically pulled about 8 mph.

Example 6

An 8 weight percent Pd on CARULITE® catalyst was prepared byimpregnating 100 g CARULITE® 200 catalyst powder (ground up in ablender) to the point of incipient wetness with 69.0 g of a watersolution containing palladium tetraamine acetate (12.6% Pd). The powderwas dried overnight at 90° C. and then calcined to 450° C. or 550° C.for 2 hours. 92 g of the resulting calcined catalyst was then combinedwith 171 g of deionized water in a ball mill to create a slurry of 35%solids. After milling for 30 minutes to a particle size 90%<9 μm, 3.1 gof National Starch x4260 acrylic latex binder (50% solids) was added,and the resulting mixture was milled for an additional 30 minutes todisperse the binder. Compositions containing 2,4 and 6 weight percent Pdon CARULITE® catalysts were similarly prepared and evaluated.

The catalysts were evaluated for ozone decomposition at room temperatureand 630,000/h space velocity using washcoated 300 cpsi (cells per squareinch) ceramic honeycombs. The catalyst samples were prepared as recitedabove. Results are summarized in Table IV. As can readily be seen, the 4and 8% Pd/CARULITE® catalysts which were calcined to 450° C. gaveequivalent initial and 45 minute ozone conversions (ca. 62 and 60%,respectively) . These results are equivalent to those of CARULITE®catalyst alone under the identical test conditions. The 2 and 4% Pdcatalysts which were calcined to 550° C. gave significantly lowerconversions after 45 minutes (47%). This is attributed to a loss insurface area at the higher temperature of calcination. The 6% catalystwas also calcined to 550° C. but did not show quite as large of anactivity drop.

TABLE IV OZONE RESULTS (300 cpsi Honeycomb, 630,000/h Space Velocity)LOADING CONVERSION (%) CONVERSION (%) CATALYST (g/in³) Initial 45Minutes Pd on CARULITE ® 200 Catalyst 4% Pd/CARULITE ® catalyst 1.8 6459 (calcined 450° C.) 8% Pd/CARULITE ® catalyst 2.0 61 60 (calcined 450°C.) 2% Pd/CARULITE ® catalyst 2.1 57 48 (calcined 550° C.) 4%Pd/CARULITE ® catalyst 1.9 57 46 (calcined 550° C.) 6% Pd/CARULITE ®catalyst 2.3 59 53 (calcined 550° C.)

Example 7

A series of tests were conducted to evaluate a variety of catalystcompositions comprising a palladium component to treat air containing0.25 ppm ozone. The air was at ambient conditions (23° C.; 0.6% water).The compositions were coated onto a 300 cell per inch ceramic(cordierite) flow through honeycomb at loadings of about 2 g of washcoatper cubic inch of substrate. The coated monoliths containing the varioussupported palladium catalysts were loaded into a 1″ diameter stainlesssteel pipe, and the air stream was passed perpendicular to the open faceof the honeycomb at a space velocity of 630,000/h. Ozone concentrationwas measured inlet and outlet of the catalyst. One alumina support usedwas SRS-II gamma alumina (purchased from Davison) characterized asdescribed in Example 1 (surface area approximately 300 m²/g) . Also usedwas a low surface area theta alumina characterized by a surface area ofapproximately 58 m²/g and an average pore radius of about 80 Angstrom.E-160 alumina is a gamma alumina characterized by a surface area ofabout 180 m²/g and an average pore radius of about 47 Angstrom. Ceriaused had a surface area about 120 m²/g and an average pore radius ofabout 28 Angstrom. Also used was dealuminated Beta zeolite with a silicato alumina ratio of approximately 250 to 1 and a surface area about 430m²/g. Carbon, a microporous wood carbon characterized with a surfacearea of about 850 m²/g, was also used as a support. Finally, a titaniapurchased from Rhone-Poulenc (DT51 grade) and characterized by a surfacearea of approximately 110 m²/g was used as a support. Results aresummarized in Table V which includes the relative weight percent ofvarious catalyst components, the loading on the honeycomb, initial ozoneconversion, and conversion after 45 minutes.

TABLE V OZONE RESULTS - (300 cpsi Honeycomb, 630,000/h Space Velocity,0.6% Water; ca. 0.25 ppm Ozone) LOADING CONVERSION (%) CONVERSION (%)CATALYST (g/in³⁾ Initial 45 Minutes I.W. 8% Pd/5% Mn/Al₂O₃ 1.8 60 55I.W. 8% Pd/5% Mn/Low 1.9 64 60 Surface Area Al₂O₃ 8% Pd/Low Surface Area1.9 56 44 Al₂O₃ 8% Pd/E-160 Al₂O₃ 2.2 61 57 4.6% Pd/CeO₂ 1.99 59 58 8%Pd/BETA Zeolite 1.9 38 32 (dealuminated) 5% Pd/C 0.5 63 61 8% Pd/DT-51TiO₂ 1.8 39 20

Example 8

Following is a preparation of CARULITE® catalyst slurry which includesvinyl acetate latex binder and is used in coating radiators whichresults in excellent adhesion of the catalyst to an aluminum radiator.

1000 g of CARULITE® 200 catalyst, 1500 g of deionized water, and 50 g ofacetic acid (5% based on CARULITE® catalyst) were combined in a 1 gallonball mill and milled for 4 hours to a particle size 90%≦7 μm. Afterdraining the resulting slurry from the mill, 104 g (5% solids basis) ofNational Starch Dur-O-Set E-646 cross linking EVA copolymer (48% solids)was added. Thorough blending of the binder was achieved by rolling theslurry on a mill without milling media for several hours. Followingcoating of this slurry onto a piece of aluminum substrate (e.g.,radiator), excellent adhesion (i.e., coating could not be wiped off) wasobtained after drying for 30 minutes at 30° C. Higher temperatures ofcuring (up to 150° C.) can be utilized if desired.

Example 9

Carbon monoxide conversion was tested by coating a variety of titaniasupported platinum compositions onto ceramic honeycombs as described inExample 6. Catalyst loadings were about 2 g/in³, and testing wasconducted using an air stream having 16 ppm carbon monoxide (dew point35° F.) at a space velocity of 315,000/h. The catalyst compositions werereduced on the honeycomb using a forming gas having 7% H₂ and 93% N₂ at300° C. for 3 hours. Compositions containing TiO₂ included 2 and 3weight percent platinum component on P25 titania; and 2 and 3 weightpercent platinum component on DT52 grade titania. DT51 grade titania waspurchased from Rhone-Poulenc and had a surface area of approximately 110m²/g. DT52 grade titania was a tungsten containing titania purchasedfrom Rhone-Poulenc and which had a surface area of approximately 210m²/g. P25 grade titania was purchased from Degussa and was characterizedas having a particle size of approximately 1 μm and a surface area ofca. 45-50 m²/g. Results are illustrated in FIG. 10.

Example 10

Example 10 relates to the evaluation of CO conversion for compositionscontaining alumina, ceria and zeolite. The supports were characterizedas described in Example 7. Compositions evaluated included 2 weightpercent platinum on low surface area theta alumina; 2 weight percentplatinum and ceria; 2 weight percent platinum on SRS-II gamma alumina,and 2 weight percent platinum on Beta zeolite. Results are illustratedin FIG. 11.

Example 11

Co conversion was measured v. temperature for compositions containing 2weight percent platinum on SRS-II gamma alumina and on ZSM-5 zeolitewhich were coated onto a 1993 Nissan Altima radiator as recited inExample 4 and tested using the same procedure to test CO as used inExample 4. Results are illustrated in FIG. 9.

Example 12

0.659 g of a solution of amine solubilized platinum hydroxide solutionhaving 17.75 weight percent platinum (based on metallic platinum) wasslowly added to 20 g of an 11.7 weight percent aqueous slurry of atitania sol in a glass beaker and stirred with a magnetic stirrer. Aone-inch diameter by one-inch long 400 cells per square inch (cpsi)metal monolith cored sample was dipped into the slurry. Air was blownover the coated monolith to clear the channels and the monolith wasdried for three hours at 110° C. At this time, the monolith was redippedinto the slurry once again and the steps of air blowing the channels anddrying at 110° C. was repeated. The twice coated monolith was calcinedat 300° C. for two hours. The uncoated metal monolith weighed 12.36 g.After the first dipping, it weighed 14.06 g, after the first drying 12.6g, after the second dipping 14.38 g and after calcination weighed 13.05g indicating a total weight gain of 0.69 g. The coated monolith had 72g/ft³ of platinum based on the metal and is designated as 72 Pt/Ti. Thecatalyst was evaluated in an air stream containing 20 ppm carbonmonoxide at a gas flow rate of 36.6 liters per minute. After thisinitial evaluation the catalyst core was reduced in a forming gas having7% hydrogen and 93% nitrogen at 300° C. for 12 hours and the evaluationto treat an air stream containing 20 ppm carbon monoxide was repeated.The reduced coated monolith as designated as 72 Pt/Ti/R. The aboverecited slurry was then evaluated using a cored sample from a ceramicmonolith having 400 cells per square inch (cpsi), which was precoatedwith 40 g per cubic foot, of 5:1 weight ratio of platinum to rhodiumplus 2.0 g per cubic inch of ES-160 (alumina) and the core had 11 cellsby 10 cells by 0.75 inches long monolith and designated as 33 Pt/7Rh/Alwas dipped into the above recited slurry and air blown to clean thechannels. This monolith was dried at 110° C. for three hours andcalcined at 300° C. for two hours. The catalyst substrate including thefirst platinum and rhodium layer weighed 2.19 g. After the first dip itweighed 3.40 g and after calcination 2.38 g showing a total weight gainof 0.19 g which is equal to 0.90 g per cubic inch of theplatinum/titania slurry. The dipped ceramic core contained 74 per cubicfoot of platinum based on the platinum metal and designated as 74Pt/Ti//Pt/Rh. Results are illustrated in FIG. 12.

Example 13

A platinum on titanium catalyst as described in the above referencedExample 12 has been used in an air stream containing 4 ppm propane and 4ppm propylene. In an air stream at a space velocity of 650,000 standardhourly space velocity. The platinum and titanium catalyst had 72 g ofplatinum per cubic foot of total catalyst and substrate used. It wasevaluated on the ceramic honeycomb as recited in Example 13. Themeasured results for propylene conversion were 16.7% at 65° C.; 19% at70° C.; 23.8% at 75° C.; 28.6% at 80° C.; 35.7% at 85° C.; 40.5% at 95°C. and 47.6% at 105° C.

Example 14

Example 14 is an illustration of a platinum component on a titaniasupport. This Example illustrates the excellent activity of platinumsupported on titania for carbon monoxide and hydrocarbon oxidation. Theevaluation was carried out using a catalyst prepared from a colloidaltitania sol to form a composition comprising 5.0 weight percent platinumcomponent based on the weight of the platinum metal and titania. Theplatinum was added to titania in the form of amine solubilized platinumhydroxide solution. It was added to colloidal titania slurry or intotitania powders to prepare a platinum and titania containing slurry. Theslurry was coated onto a ceramic monolith having 400 cells per squareinch (cpsi). Samples had coating amounts varying from 0.8-1.0 g/in. Thecoated monoliths were calcined for 300° C. for 2 hours in the air andthen reduced. The reduction was carried out at 300° C. in a gascontaining 7% hydrogen and 93% nitrogen for 12 hours. The colloidaltitania slurry contained 10% by weight titania in an aqueous media. Thetitania had a nominal particle size of 2-5nm.

Carbon monoxide conversion was measured in an air stream containing 20ppm CO. The flow rate of the carbon monoxide in various experimentsrange from space velocities of 300,000 VHSV to 650,000 VHSV at atemperature between ambient to 110° C. The air used was purified airfrom an air cylinder and where humidity was added the air was passedthrough a water bath. Where humidity was studied the relative humiditywas varied from 0-100% humidity at room temperature (25° C.). The carbonmonoxide containing air stream was passed through the ceramic monolithcoated with the catalyst compositions using a space velocity of650,000/h.

FIG. 13 represents a study using air with 20 ppm CO having to measurecarbon monoxide conversion v. temperature comparing platinum supportedon titania which has been reduced (Pt/Ti-R) at 300° C. using a reducinggas containing 7% hydrogen and 93% nitrogen for 12 hours as recitedabove with a non reduced platinum supported on titania catalyst (Pt/Ti)coating. FIG. 13 illustrates a significant advantage when using areduced catalyst.

FIG. 14 illustrates a comparison of platinum on titania which has beenreduced with varying supports including platinum on tin oxide (Pt/Sn),platinum on zinc oxide (Pt/Zn) and platinum on ceria (Pt/Ce) forcomparative sake. All of the samples were reduced at the above indicatedconditions. The flow rate of carbon monoxide in the air was 650,000shsv. As can be seen, the reduced platinum on colloidal titania hadsignificantly higher conversion results than platinum on the variousother support materials.

Hydrocarbon oxidation was measured using a 6 ppm propylene air mixture.The propylene air stream was passed through the catalyst monolith at aspace velocity of 300,000 vhsv at a temperature which varied from roomtemperature to 110° C. Propylene concentration was determined using aflame ionized detector before and after the catalyst. The results aresummarized in FIG. 15. The support used was 5% by weight based on theweight of platinum metal and yttrium oxide Y₂O₃. The comparison wasbetween reduced and non reduced catalyst. As shown in FIG. 15 reducingthe catalyst resulted in a significant improvement in propyleneconversion.

The above recited platinum supported on titania catalyst was reduced ina forming gas containing 7% hydrogen and 93% nitrogen at 500° C. for 1hour. The conversion of carbon monoxide was evaluated in 0 percentrelative humidity air at a flow rate of 500,000 vhsv. The evaluation wasconducted to determine if the reduction of the catalyst was reversible.Initially, the catalyst was evaluated for the ability to convert carbonmonoxide at 22° C. As shown in FIG. 16, the catalyst initially convertedabout 53% of the carbon monoxide and dropped down to 30% afterapproximately 200 minutes. At 200 minutes the air and carbon monoxidewas heated to 50° C. and carbon monoxide conversion increased to 65%.The catalyst was further heated to 100° C. in air and carbon monoxideand held at 100° C. for one hour, and then cooled in air to roomtemperature (about 25° C.). Initially, the conversion dropped to about30% in the period from about 225-400 minutes. The evaluation wascontinued at 100° C. to 1200 minutes at which time conversion wasmeasured at about 40%. A parallel study was conducted at 50° C. At about225 minutes the conversion was about 65%. After 1200 minutes, theconversion actually rose to about 75%. This Example shows that reductionof the catalyst permanently improves the catalysis activity.

Example 15

Example 15 is used to illustrate ozone conversion at room temperaturefor platinum and/or palladium components supported on a manganeseoxide/zirconia coprecipitate. This Example also shows a platinumcatalyst which catalyzes the conversion of ozone to oxygen and, at thesame time, oxidize carbon monoxide and hydrocarbons. Manganeseoxide/zirconia mixed oxide powders were made having 1:1 and 1:4 weightbased on Mn and Zr metals. The coprecipitate was made in accordance withthe procedure disclosed in U.S. Pat. No. 5,283,041 referenced above. 3%and 6% Pt on manganese/zirconia catalysts (1:4 weight basis of Mn to Zr)were prepared as described in Example 4. SBA-150 gamma alumina (10%based on the weight of the mixed oxide powder) was added as a binder inthe form of a 40% water slurry containing acetic acid (5% by weight ofalumina powder) and milled to a particle size 90%<10 μm. The 6% weightpercent Pd catalyst was prepared by impregnating manganese/zirconia frit(1:1 weight basis of Mn to Zr) to the point of incipient wetness with awater solution containing palladium tetraamine acetate. After drying andthen calcining the powder for two hours at 450° C., the catalyst wasmixed in a ball mill with Nalco #1056 silica sol (10% by weight ofcatalyst powder) and enough water to create a slurry of approximately35% solids. The mixture was then milled until the particle size was90%<10 μm. Various samples were reduced using a forming gas having 7% H₂and 93% N₂ at 300° C. for 3 hours. Evaluations were conducted todetermine the conversion of ozone on coated radiator minicores from a1993 Altima radiator which were approximately ½ inch by ⅞ inch by 1 inchdeep. The evaluation was conducted at room temperature using a one-inchdiameter stainless steel pipe as described in Example 7 with house air(laboratory supplied air) at a 630,000/h space velocity with an inletozone concentration of 0.25 ppm. Results are provided on Table VI.

TABLE VI SUMMARY OF FRESH ACTIVITY OZONE RESULTS - (39 cpsi NissanAltima core, 630,000/h Space Velocity; 25° C.; 0.25 ppm ozone; Houseair - ca. 0.6% water) CONVERSION CONVERSION CORE LOADING (%) (%) NO.CATALYST (g/in³) Initial 45 Minutes 1 3% Pt/MnO₂/ZrO₂ (1:4) (calcined at0.7 70.7 65.8 450° C.) 2 3% Pt/MnO₂/ZrO₂ (1:4) (calcined at 0.7 70.563.7 450° C.; reduced at 300° C.) 3 6% Pt/MnO₂/ZrO₂ (1:4) (calcined at0.68 68.2 62.3 450° C.) 4 6% Pt/MnO₂/ZrO₂ (1:4) (calcined 0.66 66 55.8450° C.; reduced at 300° C.) 5 6% Pd/MnO₂/ZrO₂ (1:1) w. 10% 0.39 38.321.1 Nalco 1056 6 MnO₂/ZrO₂ (1:1) w. 10% Nalco 0.41 58.3 44.9 1056 7MnO₂/ZrO₂ (1:1) w. 10% Nalco 0.37 55.8 41.2 1056 8 3% Pt/ZrO₂/SiO₂(calcined 450° C.) 0.79 27.4 10 9 3% Pt/ZrO₂/SiO₂ (calcined 450° C. 0.7654.2 30.1 and reduced at 300° C.)

As can be seem from Table VI Cores 1 and 2 having only 3% platinumresulted in excellent ozone conversion initially and after 45 minutesboth for reduced and unreduced catalyst. Cores 3 and 4 having a 6%platinum concentration also had excellent results but not quite as goodas the 3% platinum results. Cores 5-7 illustrate a variety of othersupport materials used which resulted in coversion of ozone. Core 5 hadpalladium on a manganese oxide/zirconia coprecipitate and resulted inlower than expected but still significant ozone conversion. Cores 6 and7 evaluations used the coprecipitate without precious metal and alsoresulted in significant ozone conversions but here again not as good aswhen using platinum as a catalyst. Core 8 was platinum on azirconia/silica support which was calcined but not reduced and Core 9was platinum on zirconia/silica support which was reduced. Both Cores 8and 9 gave some conversion but yet not as good as the conversionobtained with platinum on the coprecipitate.

In addition, carbon monoxide conversion was evaluated on 39 cpsiradiator minicores, as recited, for 3% and 6% platinum onmanganese/zirconia supports. Reduced and unreduced samples wereevaluated. For illustrative purposes, platinum on zirconia/silicasupports and platinum on CARULITE® catalyst reduced and unreduced arealso presented. As can be seen from FIG. 17, the results of 3% reducedplatinum on manganese/zirconia support were higher when compared to theother embodiments.

Example 16 (Comparative)

Ozone conversion was measured over an uncoated 1995 Ford Contourradiator at room temperature and 80° C. by blowing an air streamcontaining ozone (0.25 ppm) through the radiator channels at a 10 mphlinear velocity (630,000/h space velocity) and then measuring theconcentration of ozone exiting the back face of the radiator. The airstream had a dew point of approximately 35° F. Heated coolant was notcirculated through the radiator, but the air stream was heated asnecessary with heating tape to achieve the desired radiator temperature.Additional testing was completed with an uncoated 0.75″(L)×0.5″(W)×1.0″(D) Ford Taurus radiator “mini-core” in a 1″ diameter stainless steelpipe as described in Example 7. The air stream was heated with heatingtape to achieve the desired radiator temperature. For both tests, nodecomposition of ozone was observed up to 120° C.

Example 17

Ozone conversion was measured at various temperatures for a reduced 3%Pt/TiO₂ catalyst in the absence and in the presence of 15 ppm CO.Degussa P25 grade titania was used as the support and was characterizedas having a particle size of approximately 1 μm and a surface area ofca. 45-50 m²/g. The catalyst was coated onto a 300 cpsi ceramic(cordierite) honeycomb and was reduced on the honeycomb using a forminggas having 7% H₂ and 93% N₂ at 300° C. for 3 hours. Testing wasaccomplished as described previously in Example 7. The air stream (35°F. dewpoint) was heated with heating tape to achieve the desiredtemperature. As can be seen in FIG. 18, an approximate 5% enhancement inabsolute ozone conversion was observed from 25 to 80° C. The presence ofCO improves the conversion of ozone.

Example 18

100 g of Versal GL alumina obtained from LaRoche Industries Inc. wasimpregnated with about 28 g of Pt amine hydroxide (Pt(A)salt) diluted inwater to about 80 g of solution. 5 g of acetic acid was added to fix thePt onto the alumina surface. After mixing for half hour, the Ptimpregnated catalyst was made into a slurry by adding water to makeabout 40% solids. The slurry was ballmilled for 2 hours. The particlesize was measured to be 90% less than 10 microns. The catalyst wascoated onto a 1.5″ diameter by 1.0″ length 400 cpsi ceramic substrate togive a washcoat loading after drying of about 0.65 g/in³. The catalystwas then dried at 100° C. and calcined at 550° C. for 2 hours. Thiscatalyst was tested for C₃H₆ oxidation at temperatures between 60 and100° C. in dry air as described in Example 21.

Some of calcined Pt/Al₂O₃ sample described above was also reduced in7%H2/N2 at 400° C. for 1 hour. The reduction step was carried out byramping the catalyst temperature from 25 to 400° C. at a H2/N2 gas flowrate of 500 cc/min. The ramp temperature was about 5° C./min. Thecatalyst was cooled down to room temperature and the catalyst was testedfor C₃H₆ oxidation as described in Example 21.

Example 19

6.8 g of ammonium tungstate was dissolved in 30 cc of water and the pHadjusted to 10 and the solution impregnated onto 50 g of Versal GLalumina (LaRoche Industries Inc.). The material was dried at 100° C. andcalcined for 2 hours at 550° C. The approximately 10% by metal weight ofW on Al₂O₃ was cooled to room temperature and impregnated with 13.7 g ofPt amine hydroxide (18.3% Pt). 2.5 g of acetic acid was added and mixedwell. The catalyst was then made into a slurry containing 35% solid byadding water. The slurry was then coated over a 400 cpsi, 1.5″×1.0″diameter ceramic substrate resulting, after drying, in having a catalystwashcoat loading of 0.79 g/in³. The coated catalyst was then dried andcalcined at 550° C. for 2 hours. The catalyst was tested calcined inC₃H₆ and dry air in the temperature range 60 to 100° C.

Example 20

6.8 g of perrhenic acid (36% Re in solution) was further diluted inwater to make 10 g percent perrhenic acid solution. The solution wasimpregnated onto 25 g of Versal GL alumina. The impregnated alumina wasdried and the powder calcined at 550° C. for 2 hours. The impregnated 10weight percent based metal of Re on Al₂O₃ powder was then furtherimpregnated with 6.85 g of Pt amine hydroxide solution (Pt metal insolution was 18.3%). 5 g of acetic acid was added and mixed for a halfhour. A slurry was made by adding water to make 28% solid. The slurrywas ballmilled for 2 hours and coated onto 1.5″ diameter×1.0″ length 400cpsi ceramic substrate to give a catalyst washcoat loading of 0.51 g/in³after drying. The catalyst coated substrate was dried at 100° C. andcalcined at 550° C. for 2 hours. The catalyst was tested in the calcinedform using 60 ppm C₃H₆ and dry air in the temperature range of 60 to100° C.

Example 21

The catalyst of Examples 18, 19 and 20 were tested in a microreactor.The size of the catalyst samples was 0.5″ diameter and 0.4″ length. Thefeed was composed of 60 ppm C₃H₆ in dry air in the temperature range of25 to 100° C. The C₃H₆ was measured at 60, 70, 80, 90 and 100° C. atsteady sate condition. Results are summarized in Table VII.

TABLE VII SUMMARY RESULTS OF C3H6 CONVERSION Catalyst Pt/Al₂O₃ NameCalcined Pt/10% % C3H6 Pt/Al₂O₃ and Pt/10% W/Al₂O₃ Re/Al₂O₃ ConversionCalcined Reduced Calcined Calcined @ (Ex. 18) (Ex. 18) (Ex. 19) (Ex. 20)60° C. 0 10 9 11 70° C. 7 22 17 27 80° C. 20 50 39 45 90° C. 38 70 65 64100° C. 60 83 82 83

It is clear from the Table that addition of W or Re oxide has enhancedthe activity of the Pt/Al₂O₃ in the calcined form. The C₃H₆ conversionof the calcined Pt/Al₂O₃ was enhanced significantly when catalyst wasreduced at 400° C. for 1 hour. The enhanced activity was also observedfor the calcined catalyst by incorporation of W or Re oxides.

Example 22

This is an example of preparing high surface area cryptomelane usingMnSO₄.

Molar ratios: KMnO₄: MnSO₄: acetic acid were 1: 1.43 5.72

Molarities of Mn in solutions prior to mixing were:

0.44 M KmnO₄

0.50 M MnSO₄

FW KMnO₄=158.04 g/mol

FW MnSO₄•H₂O=169.01 g/mol

FW C₂H₄O₂=60.0 g/mol

The following steps were conducted:

1. Made a solution of 3.50 moles (553 grams) of KMnO₄ in 8.05 L of D.I.water and heated to 68° C.

2. Made 10.5 L of 2N acetic acid by using 1260 grams of glacial aceticacid and diluting to 10.5 L with D.I. water. Density of this solution is1.01 g/mL.

3. Weighed out 5.00 moles (846 grams) of manganous sulfate hydrate(MnSO₄•H₂O) and dissolved in 10,115 g of the above 2N acetic acidsolution and heated to 40° C.

4. Added the solution from 3. to the solution from 1. over 15 minuteswhile continuously stirring. After addition was complete, began heatingthe slurry according to the following heat-up rate:

1:06 pm 69.4° C.

1:07 pm 71.2° C.

1:11 pm 74.5° C.

1:15 pm 77.3° C.

1:18 pm 80.2° C.

1:23 pm 83.9° C.

1:25 pm 86.7° C.

1:28 pm 88.9° C.

5. At 1:28 pm approximately 100 mL of slurry was removed from the vesseland promptly filtered on a Büchner funnel, washed with 2 L of D.I.water, and then dried in an oven at 100° C. The sample was determined tohave a BET Multi-Point surface area of 259 m²/g.

Example 23

This is an example of preparing high surface area cryptomelane usingMn(CH₃COO)₂.

Molar ratios: KMnO₄: Mn(CH₃CO₂)₂: acetic acid were 1:1.43:5.72

FW KMnO₄=158.04 g/mol Aldrich Lot #08824MG

FW Mn(CH₃CO₂)₂•H₂O=245.09 g/mol Aldrich Lot #08722HG

FW C₂H₄O₂=60.0 g/mol

1. Made a solution of 2.0 moles (316 grams) of KMnO₄ in 4.6 L of D.I.water and heated to 60° C. by heating on hot plates.

2. Made up 6.0 of 2N acetic acid by using 720 grams of glacial aceticacid and diluting to 6.0 L with D.I. water. Density of this solution is1.01 g/mL.

3. Weighed out 2.86 moles (700 grams) of manganese (II) acetatetetrahydrate [Mn(CH₃CO₂)₂.4H₂O] and dissolved in 5780 g of the above 2Nacetic acid solution (in the reactor vessel). Heated to 60° C. in thereactor vessel.

4. Added the solution from 1. to the solution from 3. while maintainingthe slurry at 62-63° C. After complete addition, gently heated theslurry according to the following:

82.0° C. at 3:58 pm

86.5° C. at 4:02 pm

87.0° C. at 4:06 pm

87.1° C. at 4:08 pm

shut off heat

then quenched the slurry by pumping 10 L of D.I. water into the vessel.This cooled the slurry to 58° C. at 4:13 pm.

The slurry was filtered on Büchner funnels. The resulting filter cakeswere reslurried in 12 L of D.I. water then stirred overnight in a 5gallon bucket using a mechanical stirrer. The washed product wasrefiltered in the morning then dried in an oven at 100° C. The samplewas determined to have a BET Multi-Point surface area of 296 m²/g. Theresulting cryptomelane is characterized by the XRD pattern of FIG. 20.It is expected to have an IR spectrum similar to that shown in FIG. 19.

Example 24

Following is a description of the ozone testing method for determiningpercent ozone decomposition used in this Example. A test apparatuscomprising an ozone generator, gas flow control equipment, waterbubbler, chilled mirror dew point hygrometer, and ozone detector wasused to measure the percent ozone destroyed by catalyst samples. Ozonewas generated in situ utilizing the ozone generator in a flowing gasstream comprised of air and water vapor. The ozone concentration wasmeasured using the ozone detector and the water content was determinedutilizing the dew point hygrometer. Samples were tested as 25° C. usinginlet ozone concentrations of 4.5 to 7 parts per million (ppm) in a gasstream flowing at approximately 1.5 L/minute with a dew point between15° C. and 17° C. Samples were tested as particles sized to −25/+45 meshheld between glass wool plugs in a ¼″ I.D. Pyrex® glass tube. Testedsamples filled a 1 cm portion of the glass tube.

Sample testing generally required between 2 to 16 hours to achieve asteady state of conversion. Samples typically gave close to 100%conversion when testing began and slowly decreased to a “leveled off”conversation that remained steady for extended periods of time (48hours). After a steady state was obtained, conversions were calculatedfrom the equation: % ozone conversion=[(1−(ozone concentration afterpassing over catalyst)/(ozone concentration before passing overcatalyst)]*100.

Ozone destruction testing on the sample of Example 22 showed 58%conversion.

Ozone destruction testing on the sample of Example 23 showed 85%conversion.

Example 25

This example is intended to illustrate that the method of Example 23generated “clean” high surface area cryptomelane for which the ozonedestruction performance was not further enhanced by calcination andwashing. A 20 gram portion of the sample represented by Example 23 wascalcined in air at 200° C. for 1 hour, cooled to room temperature, thenwashed at 100° C. in 200 mL of D.I. water by stirring the slurry for 30minutes. The resulting product was filtered and dried at 100° C. in anoven. The sample was determined to have BET Multi-Point surface area of265 m²/g. Ozone destruction testing on the sample showed 85% conversion.A comparison to the testing of the sample of Example 23 demonstratedthat no benefit in ozone conversion was realized from the washing andcalcination of the sample of Example 23.

Example 26

Samples of high surface area cryptomelane were obtained from commercialsuppliers and modified by calcination and/or washing. As received andmodified powders were tested for ozone decomposition performanceaccording to the method of Example 24 and characterized by powder X-raydiffraction, infrared spectroscopy, and BET surface area measurements bynitrogen adsorption.

Example 26a

A commercially supplied sample of high surface area cryptomelane(Chemetals, Inc., Baltimore, Md.) was washed for 30 minutes in D.I.water at 60° C., filtered, rinsed, and oven-dried at 100° C. Ozoneconversion of the as received sample was 64% compared to 79% for thewashed material. Washing did not change the surface area or crystalstructure of this material (223 m²/g cryptomelane) as determined bynitrogen adsorption and powder X-ray diffraction measurements,respectively. However, infrared spectroscopy showed the disappearance ofpeaks at 1220 and 1320 wavenumbers in the spectrum of the washed sampleindicating the removal of sulfate group anions.

Example 26b

Commercially supplied samples of high surface area cryptomelane(Chemetals, Inc., Baltimore, Md.) were calcined at 300° C. for 4 hoursand 400° C. for 8 hours. Ozone conversion of the as received materialwas 44% compared to 71% for the 300° C. calcined sample and 75% for the400° C. calcined sample. Calcination did not significantly change thesurface area or crystal structure of the 300° C. or 400° C. samples (334m²/g cryptomelane). A trace of Mn₂O₃ was detected in the 400° C. sample.Calcination causes dehydroxylation of these samples. Infraredspectroscopy show a decrease in the intensity of the band between 2700and 3700 wavenumbers assigned to surface hydroxyl groups.

Example 27

The addition Pd black (containing Pd metal and oxide) to high surfacearea cryptomelane is found to significantly enhance ozone decompositionperformance. Samples were prepared comprising Pd black powder physicallymixed with powders of (1) a commercially obtained cryptomelane (the 300°C. calcined sample described in Example 26b) and (2) the high surfacearea cryptomelane synthesized in Example 23 calcined at 200° C. for 1hour. The samples were prepared by mixing, in a dry state, powder of Pdblack and cryptomelane in a 1:4 proportion by weight. The dry mixturewas shaken until homogeneous in color. An amount of D.I. water was addedto the mixture in a beaker to yield 20-30% solids content, thus forminga suspension. Aggregates in the suspension were broken up mechanicallywith a stirring rod. The suspension was sonicated in a Bransonic® Model5210 ultrasonic cleaner for 10 minutes and then oven dried at 120-140°C. for approximately 8 hours.

The ozone conversion for the commercially obtained cryptomelane calcinedat 300° C. was 71% as measured on the powder reactor (Example 26b). Asample of this product was mixed with 20 weight percent Pd black yielded88% conversion.

The cryptomelane sample prepared as in Example 23 calcined at 200° C.had 85% conversion. Performance improved to 97% with 20 weight percentPd black added.

Example 28

1500 g of high surface area manganese dioxide (cryptomelane purchasedfrom Chemetals) and 2250 g of deionized water were combined in a onegallon ball mill and milled for 1.5 hours to a particle size 90%≦7 μm.After draining the resulting slurry from the mill into a separate 1gallon container, sufficient KOH (20% solution in DI water) was added toraise the pH to ca. 9.5. Additional KOH was added over the next severaldays to maintain a pH of 9.5. Subsequently, 294 g (10% solids basis) ofNational Starch x-4280 acrylic latex polymer (51% solids) was added.Thorough blending of the binder was achieved by rolling the containercontaining the slurry on a two roll mill. The container contained nomilling media such as ceramic milling balls. Slurry made according tothis process was coated onto a variety of substrates and exhibitedexcellent adhesion. Such substates included a porous monolithic support(eg. ceramic honeycomb) onto which the coating was applied by dippingthe honeycomb into the slurry. The slurry was also spray coated onto analuminum radiator. It was also dip coated on to small radiator minicoresof the type recited above. Additionally, polyfiber filter media of thetype used to filter air was coated by dipping or spraying. Typically,the samples were coated with loadings which could vary from 0.15 to 1.5grams per cubic inch. The samples were air dried at 30° C. until dry,typically for at least two hours. Excellent catalyst adhesion wasattained in each case (i.e. coating could not be wiped off). Highertemperatures of drying (up to 150° C.) can be utilized if desired. Thelatex cures during drying.

Example 29

To 96.56 g of the ball milled catalyst slurry obtained in Example 1(before KOH addition) was added 3.20 g (3% solids basis) ofRhone-Poulenc Colloid 226 polymeric dispersant. After rolling themixture on a roll mill for several hours, 7.31 g (10% solids basis) ofNational Starch x-4280 acrylic latex polymer (51% solids) was added. Asin Example 28, thorough blending of the binder was achieved by rollingthe container containing the slurry on a two roll mill. The containercontained no milling media such as ceramic milling balls. Slurry madeaccording to this process was coated onto a variety of substrates andexhibited excellent adhesion. Such substates included a porousmonolithic support (eg. ceramic honeycomb) onto which the coating wasapplied by dipping the honeycomb into the slurry. The slurry was alsodip coated on to small radiator minicores of the type recited above.Typically, the samples were coated with loadings which could vary from0.15 to 1.5 grams per cubic inch. The samples were air dried at 30° C.until dry, typically for at least two hours. Excellent catalyst adhesionwas attained in each case (i.e. coating could not be wiped off). Highertemperatures of drying (up to 150° C.) can be utilized if desired. Thelatex cures during drying.

Example 30

8.9 grams of D.I. water was added to 1.1 grams of TiO2 nano powder in abeaker. An ammonia/water concentrate was added to adjust the pH to 9.5.A solution of amine solubilized platinum hydroxide having 17.75 weightpercent platinum (based on metallic platinum) was slowly added, withmixing to obtain 5% by weight of platinum on titania. Then a solution ofpalladium nitrate containing 20% by weight based on palladium metal wasadded, with mixing to obtain 14.3% palladium on the titania. A one-inchdiameter by one-inch long 400 cells per square inch (cpsi) metalmonolith cored sample was dipped into the slurry. Air was blown over thecoated monolith to clear the channels and the monolith was dried forthree hours at 110° C. At this time, the monolith was redipped into theslurry once again and the steps of air blowing the channels and dryingat 110° C. was repeated. The twice coated monolith was calcined at 300°C. for two hours. After this initial evaluation the catalyst core wasreduced in a forming gas having 7% hydrogen and 93% nitrogen at 300° C.for 12 hours. The catalyst was evaluated in an air stream containing 20ppm carbon monoxide and 20 ppm of hydrocarbons based on C₁. Thehydrocarbons were evaluated in the presence of the 20 ppm CO. Thehydrocarbons evaluated were ethylene C₂═; propylene C₃═; and pentene C₅═at a gas flow rate of 36.6 liters per minute which corresponds to300,000 standard hourly space velocity (SHSV). The air stream was at 30%relative humidity (RH). Results are illustrated in FIG. 21.

The adhesion of catalytic and adsorption compositions to surfaces, e.g.,metal surfaces, may be improved by the incorporation of clay minerals asadhesion promoters. Such clay minerals include but are not limited toattapulgite, smectites (e.g., montmorillonite, bentonite, beidellite,nontronite, hectorite, saponite, etc.), kaolinite, talc, micas, andsynthetic clays (e.g., Laponite sold by Southern Clay Products).Attapulgite is preferred. In manganese dioxide catalyst coatings, forexample, even at normal auto radiator operating temperatures (typicallyless than about 100° C.), coatings prepared with acrylic-based polymerssuffer from a loss in adhesion which is attributed to gradualdecomposition of the binder by the manganese dioxide catalyst. This isunexpected since acrylic-based polymer binders are known to be stable attemperatures in excess of about 150° C.

Clays are not commonly used as adhesion promoters in low temperaturecure catalytic or adsorption coatings. While they do have wide rangingapplications in the coatings industry as fillers and suspension aids(e.g., paints), they are not intentionally used as adhesion promoters.We have found that the use of clay minerals in manganese dioxidecatalyst slurries unexpectedly improves the adhesion of the resultingcatalyst coatings to metal surfaces including aluminum auto radiator finsurfaces. In contrast, coatings prepared without the clay suffer from asevere loss of adhesion. The loss in adhesion is believed to result fromthe catalytic decomposition of the organic acrylic-based polymer. Thiseffect has been observed over the long term with road aged non-claycontaining radiator coatings (e.g., after 50,000-100,000 miles ofdriving). Heat treatment of the catalyst coating at 150° C. is believedto accelerate the decomposition process of the acrylic based adhesionagent. The effect has been quantified by measuring the amount of coatinglost from small pieces of heat-treated radiators after ultrasonicatingthe pieces in water for five minutes. For coatings prepared without clayadded to the catalyst slurry, up to 100% coating loss has been observedafter heat treatment at 150° C. for 24 hours. When clay is incorporatedinto the coating, however, significantly less coating is lost after thesame heat treatment. Based on these observations, we believe thatincorporation of clays such as attapulgite will significantly improveadhesion and durability of radiator coatings over the life of a vehicle(e.g., 100,000 to 150,000 miles).

Additional preferred metal surface adhesion promoting materials forcatalytic and adsorption compositions are water based silicone resinpolymer emulsions. These are particularly useful as adhesion aids inmanganese dioxide catalyst coatings for use on metal surfaces such asauto radiator surfaces including aluminum radiator surfaces. Aspreviously mentioned, long-term road testing of catalytic coatings whenapplied to auto radiator surfaces have shown that even at normalradiator operating temperatures (typically less than about 100° C.),coatings that have been prepared with conventional acrylic-based polymerbinders suffer from a loss in adhesion over the life of the vehicle(e.g., after 100,000 miles driving). The observed loss in adhesion isattributed to gradual decomposition of the acrylic-based binder by theMnO₂ catalyst. This is unexpected since acrylic-based binders are knownto be stable at temperatures in excess of 150° C.

Water based silicone polymer emulsions are not commonly used as adhesionaids in catalytic and adsorption composition coatings. However, they dohave application in various coating formulations used in the paint andtextile industries. For example, they are used to provide binding andwater repellency in ambient temperature cure paint coatings (e.g.concrete basement walls), and they also find use as the primary binderprecursor in high temperature paints (e.g. mufflers and smoke stacks).Whereas in the former application, the silicone polymer retains itscompositional integrity, in the latter application the organicsubstituents of the polymer are “burned” out leaving a completelyinorganic network of Si—O—Si chains as the pigment binder.

We have found that the use of water based silicone polymer emulsionsdramatically improves the adhesion of e.g. manganese dioxide catalystcoatings to aluminum radiator fin surfaces. In contrast, coatingsprepared with conventional acrylic-based polymer binders known in theart suffer from a severe loss of adhesion. The loss in adhesion forconventional binder systems after 150° C. heat treatment (acceleratedaging test) confirms results obtained from long-term on-road vehicletests which also showed that coatings prepared with the conventionalbinders suffered from a degradation in adhesion over the life of thevehicle even at standard radiator operating temperatures (less thanabout 100° C.). In both on-road and accelerated aging testing, the lossin adhesion is believed to result from the catalytic decomposition ofthe organic acrylic-based binder, and at the higher temperature (e.g.,150°, this process is accelerated. The effect has been quantified bymeasuring the amount of coating lost from small pieces of heat treatedradiators after ultrasonicating the pieces in water for five minutes.For coatings prepared from conventional acrylic latex binders, up to100% coating loss has been observed after heat treatment at 150° C. for24 hours. When silicone latex adhesion aids are used, however,significantly less coating is lost after similar treatment. Even informulations where only a small amount of the silicone adhesion aid isused in conjunction with standard acrylic-based binder (e.g. a 3:1 ratioof acrylic to silicone binders), a dramatic improvement in coatingadhesion is observed after heat treatment at 150° C. Based on theseobservations, we believe that utilization of silicone polymer adhesionaids will significantly improve adhesion and durability of manganesedioxide radiator coatings over the life of a vehicle (e.g., 100,000 to150,000 miles).

In one embodiment, the benefit of the silicone polymer is obtained byincorporating the water based silicone latex emulsion into the catalystslurry formulation prior to coating. In an additional embodiment,however, the benefit of the silicone polymer can be obtained byapplication of a dilute solution of the silicone latex over the driedcatalyst coating. The silicone latex is believed to penetrate thecoating, and upon drying, leaves a porous cross-linked polymer “network”which significantly improves adhesion of the coating even after heattreatment at 150° C.

The following examples will help to explain the advantages of theinvention in further detail.

The use of a combination of clay minerals and water based silicone resinpolymer emulsions is anticipated to produce an even greater improvementin the adhesion of catalyst and adsorption compositions to metalsurfaces than when either adhesion aid is used alone. In particular MnO₂catalyst adhesion to metal surfaces is anticipated to be improved.

Example I

A) Slurry Preparation:

In a one gallon ball mill, 1,000 g of manganese dioxide(cryptomelane)was combined with 1,500 g of DI water and milled for approximately 15minutes. The MnO₂ had a surface area of ca. 220m²/g, an average particlesize of ca.3.5 μm, and was purchased from Chemetals. After milling, theresulting slurry was drained from the mill. Subsequently, 3% RHODOLINE®226/35 dispersant (solids basis relative to MnO₂ solids) was added, andthe resulting slurry was mixed for 5-10 minutes on a roll mill. TheRHODOLINE® 226/35 dispersant was purchased from Rhodia.

Approximately 100 g of the MnO₂ slurry prepared above containing 3%RHODOLINE® 226/35 dispersant was placed in a separate container. To thiswas added 5% ATTAGEL® 50 (“ATTAGEL®”) suspension aid (solid basisrelative to MnO₂ solids). The ATTAGEL® was added in the form of a“pre-gel” prepared by dispersing ATTAGEL® powder in DI water (13%ATTAGEL® solids) under high shear. Mixing of the ATTAGEL® pre-gel intothe MnO₂ slurry was achieved by rapid shaking of the slurry container.Additionally, the slurry was mixed for 5-10 minutes on a roll mill. Thefollowing ingredients were then added sequentially: 7.5% RHOPLEX® P-376acrylic binder, 2.5% SILRES® M-50E silicone binder, 1% XLO-HVP cellulosethickening agent, 0.5% RHODASURF BC-720 wetting agent, and 0.57%NUOSEPT® 95 preservative. All ingredient quantities were based on solidsrelative to MnO₂. Each ingredient was added separately, and theresulting formulations were mixed for 5-10 minutes on a roll mill beforeaddition of the next ingredient. The XLO-HVP was added in the form of a2.5% solution that was prepared by dispersing the XLO-HVP powder in DIwater under high shear. The total solids of the final slurry formulation(“A”) was then reduced to 22%. The ATTAGEL® 50 suspension aid wasobtained from Engelhard Corporation, the RHOPLEX® P-376 acrylic binderwas purchased from Rohm & Haas Company, the SILRES® M-50E siliconebinder was purchased from Wacker Silicones, the BC-720 wetting agent waspurchased from Rhodia, the XLO-HVP thickener was purchased fromAkzo-Nobel, and the NUOSEPT® 95 preservative was purchased fromHuls-Creanova.

Similarly, two additional formulations were prepared each usingapproximately 100 g of the MnO₂ slurry prepared above containingRHODOLINE® 226/35 dispersant. Modifications to the exact slurrycomposition were made as noted below. All ingredient quantities werebased on solids relative to MnO₂. Each ingredient was added separately,and the resulting formulations were mixed for 5-10 minutes on a rollmill before addition of the next ingredient. The second slurry (“B”) hada composition of 10% ATTAGEL® 50 suspension aid, 7.5% P-376 acrylicbinder, 2.5% SILRES® M-50E silicone binder, 2% XLO-HVP cellulosethickening agent, and 0.5% RHODASURF BC-720 wetting agent. The thirdslurry (“C”) had a composition of 15% ATTAGEL® 50 suspension aid, 7.5%P-376 acrylic binder, 2.5% SILRES® M-50E silicone binder, 1.5% XLO-HVPcellulose thickening agent, and 0.5% RHODASURF BC-720 wetting agent.

B) Adhesion Testing:

A Ford Taurus radiator was cut into small pieces (hereinafter referredto as radiator “minicores”) with approximate dimensions of⅞″(W)×⅝″(H)×1″(D). Three minicores were then coated with the threeslurry formulations “A”, “B”, and “C”, prepared above. This wasaccomplished by dipping the minicores in each slurry, allowing theslurry to drain out, and then using an air-knife to blow out anyremaining excess. The coated cores were then dried in a forced airconvection oven at 90° C. for approximately 30 minutes. The loading ofcoating on the minicores was approximately 0.30-0.40 g/in³.

The coated radiator minicores were then placed in a forced airconvection oven for 24 hours at 150° C. After the 24 hour heat treatmentperiod, the samples were subjected to ultrasonic adhesion testing. Firstthe minicores were weighed, and then they were placed in separate glassbeakers filled with DI water. The glass beakers were subsequently placedin a Bransonic Model 42 ultrasonicator filled with DI water to the samelevel as in the beakers. The samples were sonicated for two minutes,dried in an oven at 90° C. for approximately 30 minutes, and thenre-weighed to determine any coating loss. The sonication procedure wasthen repeated for an additional three minutes and a final calculation ofpercent coating loss was made. The data was normalized to a constantinitial loading of 0.40 g/in³, which corresponded to a total coatingloading of 0.16 g.

Coating loss results for the three slurry formulations are summarized inTable A. The data shows that as the quantity of ATTAGEL® in theformulation was increased, adhesion of the catalyst coating after heattreatment at 150° C. correspondingly was improved.

Coating Ozone Loss Conversion Formulation Composition (%) (%) A 3%RHODOLINE ® 47 (NM-18635- 226/35 45) 5% ATTAGEL ® 50 7.5% RHOPLEX ® P-376 1% XLO-HVP 0.5% RHODASURF BC-720 0.57% NUOSEPT ® 95 B 3% RHODOLINE ®32 30 (NM-18688-3- 226/35 111) 10% ATTAGEL ® 50 7.5% RHOPLEX ® P- 3762.5% SILRES ® M- 50E 2% XLO-HVP 0.5% RHODASURF BC-720 C 3% RHODOLINE ®21 32 (NM-18688-3- 226/35 117) 15% ATTAGEL ® 50 7.5% RHOPLEX ® P- 3762.5% SILRES ® M- 50E 1.5% XLO-HVP 0.5% RHODASURF BC-720

C) Catalytic Activity Testing

A 400 cpsi ceramic honeycomb block was cut into small pieces (hereafterreferred to as ceramic minicores) with approximate dimensions of⅞″(Diameter)×2″(D). Three minicores were then coated with the slurryformulations “A”, “B”, and “C”, prepared above. This was accomplished bydipping the minicores in each slurry, allowing the slurry to drain out,and then using an air-knife to blow out any remaining excess. The coatedcores were then dried in a forced air convection oven at 90° C. forapproximately 30 minutes. The loading of coating on the minicores wasapproximately 0.30-0.40 g/in³.

Catalytic activity of the three samples was measured by passingozone-containing air over the minicores in a laboratory reactor. Thetemperature of the catalyst was 75° C., the space velocity of the airpassing through the catalyst minicore was 2,500,000/h, the dew point ofthe air was approximately 15° C., and the ozone concentration wasapproximately 250 ppb. The ozone concentration in the air stream wasmeasured before and after the catalyst using a Dasibi 1008-AH ambientozone monitor. The catalytic activity test was accomplished at very highspace velocity in an effort to assess any differences in catalyticperformance under very rigorous flow conditions. Airflow under normalradiator operating conditions would be approximately 2-4 times less. Theozone conversion results summarized in Table A show that incorporationof ATTAGEL® into the slurry formulation had essentially no effect oncatalytic performance.

Example II

Two catalyst slurry formulations were prepared according to the generalprocedure outlined in Example I. Modifications to the exact chemicalcompositions were made as noted below. All ingredient quantities werebased on solids relative to MnO₂. Each ingredient was added separately,and the resulting formulations were subsequently mixed for 5-10 minuteson a roll mill before addition of the next ingredient. The first slurry(“D”) had a composition of 3% RHODOLINE® 226/35 dispersant, 13% RHOPLEX®P-376 acrylic binder, and 3.5% ACRYSOL® RM-8W associative thickener. Thesecond slurry (“E”) had a composition of 3% RHODOLINE® 226/35dispersant, 3% ATTAGEL® 50 suspension aid, 13% RHOPLEX® P-376 acrylicbinder, and 2% XLO-HVP cellulose thickener. The RHODOLINE® 226/35dispersant was purchased from Rhodia, the RHOPLEX® P-376 acrylic binderand the ACRYSOL® RM-8W thickener were purchased from Rohm & HaasCompany, the ATTAGEL® 50 suspension aid was obtained from EngelhardCorporation, and the XLO-HVP thickener was purchased from Akzo-Nobel. Asdescribed in Example I, Ford Taurus radiator minicores were first coatedwith the two slurry formulations and then were subjected to ultrasonicadhesion testing after heat treatment at 150° C. for 24 hours. Adhesiontest results are summarized in Table B. The data shows that whenATTAGEL® 50 suspension aid was incorporated into the catalystformulation, adhesion of the catalyst coating after treatment at 150° C.was dramatically improved.

Formulation Composition Coating Loss (%) D 3% RHODOLINE ® 100(NM-18593-6-8) 226/35 13% RHOPLEX ® P-376 3.5% ACRYSOL ® RM-8W E 3%RHODOLINE ® 55 (NM-18635-22-91) 226/35 3% ATTAGEL ® 50 13% RHOPLEX ®P-376 2% XLO-HVP

Example III

Two catalyst slurry formulations were prepared according to the generalprocedure outlined in Example I. Modifications to the exact chemicalcompositions were made as noted below. All ingredient quantities werebased on solids relative to MnO₂. Each ingredient was added separately,and the resulting formulations were subsequently mixed for 5-10 minuteson a roll mill before addition of the next ingredient. The first slurry(“F”) had a composition of 3% RHODOLINE® 226/35 dispersant, 13% NACRYLICX-4280 acrylic binder, and 3.5% ACRYSOL® RM-8W associative thickener.The second slurry (“G”) had a composition of 3% RHODOLINE® 226/35dispersant, 3% ATTAGEL® 50 suspension aid, 10% NACRYLIC X-4280 acrylicbinder, and 1.5% XLO-HVP cellulose thickener. The RHODOLINE® 226/35dispersant was purchased from Rhodia, the NACRYLIC X-4280 acrylic binderwas purchased from National Starch and Chemical Company, the ACRYSOL®RM-8W thickener was purchased from Rohm & Haas Company, the ATTAGEL® 50suspension aid was obtained from Engelhard Corporation, and the XLO-HVPthickener was purchased from Akzo-Nobel.

As described in Example I, Ford Taurus radiator minicores were firstcoated with the two slurry formulations and then subjected to ultrasonicadhesion testing after heat treatment at 150° C. for 24 hours. Adhesiontest results are summarized in Table C. The data shows that whenATTAGEL® 50 suspension aid was incorporated into the catalystformulation, adhesion of the catalyst coating after treatment at 150° C.was dramatically improved even when less acrylic binder was used in thecoating.

Coating Ozone Loss Conversion Formulation Composition (%) (%) F 3%RHODOLINE ® 100 32 (GM-18610- 226/35 43-1) 13% NACRYLIC X-4280 3.5%ACRYSOL ® RM-8W G 3% RHODOLINE ® 64 32 (NM-18635- 226/35 1-4) 3%ATTAGEL ® 50 10% NACRYLIC X-4280 1.5% XLO-HVP

As described in Example I, 400 cpsi ceramic minicores were first coatedwith the two catalyst slurry formulations and then subjected tocatalytic activity testing. Ozone conversion results are summarized inTable C. The data shows that incorporation of the ATTAGEL® 50 into theslurry formulation had no effect on catalytic activity.

Example IV

Three catalyst slurry formulations were prepared according to thegeneral procedure outlined in Example I. Modifications to the exactchemical compositions were made as noted below. All ingredientquantities were based on solids relative to MnO₂. Each ingredient wasadded separately, and the slurries were subsequently mixed for 5-10minutes on a roll mill before addition of the next ingredient. The firstslurry (“H”) had a composition of 3% RHODOLINE® 226/35 dispersant, 3%ATTAGEL® 50 suspension aid, 13% RHOPLEX® P-376 acrylic binder, and 2%XLO-HVP cellulose thickener. The second slurry (“I”) had a compositionof 3% RHODOLINE® 226/35 dispersant, 3% ATTAGEL® 50 suspension aid, 9.75%RHOPLEX® P-376 acrylic binder, 3.25% SILRES® M-50E silicone latexbinder, and 1.5% XLO-HVP cellulose thickener. The third slurry (“J”) hada composition of 3% RHODOLINE® 226/35 dispersant, 3% ATTAGEL® 50suspension aid, 9.75% RHOPLEX® P-376 acrylic binder, 3.25% SILRES®MP-42E silicone latex binder, and 1.5% XLO-HVP cellulose thickener. TheRHODOLINE® 226/35 dispersant was purchased from Rhodia, the RHOPLEX®P-376 acrylic binder was purchased from Rohm & Haas Company, theATTAGEL® 50 suspension aid was obtained from Engelhard Corporation, theSILRES® M-50E and MP-42E silicone latex binders were purchased fromWacker Silicones, and the XLO-HVP thickener was purchased fromAkzo-Nobel.

As described in Example I, Ford Taurus radiator minicores were firstcoated with the two slurry formulations and then were subjected toultrasonic adhesion testing after heat treatment at 150° C. for 24hours. Adhesion test results are summarized in Table D. Formulation “H”,which contained only the conventional acrylic binder, had the highestcoating loss of 55%, Formulations “I” and “J” in which some of theacrylic binder was replaced with a silicone binder, had significantlyless coating loss (35 and 28%, respectively). The data shows that evenwhen a small amount of the RHOPLEX® P-376 acrylic binder is replacedwith a silicone binder (while maintaining the same total binder level inthe slurry formulation), adhesion of the catalyst coating aftertreatment at 150° C. is dramatically improved.

As described in Example I, 400 cpsi ceramic minicores were first coatedwith the three catalyst slurry formulations and then subjected tocatalytic activity testing. Ozone conversion results are summarized inTable D. The data shows that incorporation of silicone binder into theslurry formulation has essentially no or only a very minor effect oncatalytic performance depending on the specific silicone used.

TABLE D Coating Adhesion and Catalytic Activity Data for Example IVOzone Coating Conversion Formulation Composition Loss (%) (%) H 3%RHODOLINE ® 55 28 (NM-18635-22- 226/35 91) 3% ATTAGEL ® 50 13% RHOPLEX ®P- 376 2% XLO-HVP I 3% RHODOLINE ® 35 27 (NM-18635-22- 226/35 93) 3%ATTAGEL ® 50 9.75% RHOPLEX ® P-376 3.25% SILRES ® M-50E 1.5% XLO-HVP J3% RHODOLINE ® 28 24 (NM-18635-23- 226/35 94) 3% ATTAGEL ® 50 9.75%RHOPLEX ® P-376 3.25% SILRES ® MP-42E 1.5% XLO-HVP

Example V

Four catalyst slurry formulations were prepared according to the generalprocedure outlined in Example I. Modifications to the exact chemicalcompositions were made as noted below. All ingredient quantities werebased on solids relative to MnO₂. Each ingredient was added separately,and the slurries were subsequently mixed for 5-10 minutes on a roll millbefore addition of the next ingredient. The first slurry (“K”) had acomposition of 3% RHODOLINE® 226/35 dispersant, 13% NACRYLIC X-4280acrylic binder, and 3.5% ACRYSOL® RM-8W associative thickener. Thesecond slurry (“L”) had a composition of 3% RHODOLINE® 226/35dispersant, 3.25% NACRYLIC X-4280 acrylic binder, and 9.75% SILRES®M-50E silicone binder. The third slurry (“M”) had a composition of 3%RHODOLINE® 226/35 dispersant, 3.25% NACRYLIC X-4280 acrylic binder, and9.75% SILRES® MP-42E silicone binder. The fourth slurry (“N”) had acomposition of 3% RHODOLINE® 226/35 dispersant, 3.25% NACRYLIC X-4280acrylic binder, and 9.75% SM-2112 silicone binder. The RHODOLINE® 226/35dispersant was purchased from Rhodia, the NACRYLIC X-4280 acrylic binderwas purchased from National Starch and Chemical Company, the ACRYSOL®RM-8W thickener was purchased from Rohm & Haas Company, the SILRES®M-50E and MP-42E silicone binders were purchased from Wacker Silicones,and the SM-2112 silicone binder was purchased from GE Silicones.

As described in Example I, Ford Taurus radiator minicores were coatedwith the four catalyst slurry formulations and then subjected toultrasonic adhesion testing after heating the samples at 150° C. for 24hours. Adhesion test results are summarized in Table E. The data showsthat even when a small amount of the NACRYLIC X-4280 acrylic binder isreplaced with several different silicone binders (while maintaining thesame total binder level in the formulation), adhesion of the catalystcoating after treatment at 150° C. is dramatically improved.

TABLE E Coating Adhesion Data for Example V Coating FormulationComposition Loss (%) K 3% RHODOLINE ® 100 (GM-18610-43- 226/35 1) 13%NACRYLIC X- 4280 3.5% RM-8W L 3% RHODOLINE ® 28 (GM-18641-18- 226/35 1)3.25% NACRYLIC X- 4280 9.75% SILRES ® M- 50E M 3% RHODOLINE ® 18(GM-18641-18- 226/35 2) 3.25% NACRYLIC X- 4280 9.75% SILRES ® MP- 42E N3% RHODOLINE ® 33 (GM-18641-18- 226/35 4) 3.25% NACRYLIC X- 4280 9.75%SM-2112

Example VI

Three catalyst slurry formulations were prepared according to thegeneral procedure outlined in Example I. Modifications to the exactchemical compositions were made as noted below. All ingredientquantities were based on solids relative to MnO₂. Each ingredient wasadded separately, and the slurries were subsequently mixed for 5-10minutes on a roll mill before addition of the next ingredient. The firstslurry (“O”) had a composition of 3% RHODOLINE® 226/35 dispersant, 13%RHOPLEX® AC-261 acrylic binder, and 3.5% ACRYSOL® RM-8W associativethickener. The second slurry (“P”) had a composition of 3% RHODOLINE®226/35 dispersant, 6.5% RHOPLEX® AC-261 acrylic binder, and 6.5% SILRES®M-50E silicone binder. The third slurry (“Q”) had a composition of 3%RHODOLINE® 226/35 dispersant, 6.5% RHOPLEX® AC-261 acrylic binder, and6.5% SILRES® MP-42E silicone binder. The RHODOLINE® 226/35 dispersantwas purchased from Rhodia, the RHOPLEX® AC-261 acrylic binder andACRYSOL® RM-8W thickener were purchased from Rohm & Haas Company, andthe SILRES® M-50E and MP-42E silicone binders were purchased from WackerSilicones.

As described in Example I, Ford Taurus radiator minicores were firstcoated with the three slurry formulations and then they were subjectedto ultrasonic adhesion testing after heat treatment at 150° C. for 24hours. Adhesion test results are summarized in Table F. The data showsthat when some of the RHOPLEX® AC-261 acrylic binder is replaced with asilicone binder (while maintaining the same total binder level in theformulation), adhesion of the catalyst coating after treatment at 150°C. is dramatically improved.

TABLE F Coating Adhesion Data for Example VI Coating FormulationComposition Loss (%) O 3% RHODOLINE ® 100 (NM-18593-48- 226/35 6-7) 13%RHOPLEX ® AC- 261 3.5% RM-8W P 3% RHODOLINE ® 53 (NM-18593-52- 226/3513) 6.5% RHOPLEX ® AC-261 6.5% SILRES ® M- 50E Q 3% RHODOLINE ® 36(NM-18593-52- 226/35 14) 6.5% RHOPLEX ® AC-261 6.5% SILRES ® MP- 42E

Example VII

Two catalyst slurry formulations were prepared according to the generalprocedure outlined in Example I. Modifications to the exact chemicalcompositions were made as noted below. All ingredient quantities werebased on solids relative to MnO₂. Each ingredient was added separately,and the slurries were subsequently mixed for 5-10 minutes on a roll millbefore addition of the next ingredient. The first slurry (“R”) had acomposition of 3% RHODOLINE® 226/35 dispersant, 8% ATTAGEL® 50suspension aid, 6% RHOPLEX® P-376 acrylic binder, 6% DUROSET Elite 22EVA binder, 2.5% XLO-HVP cellulose thickening agent, 0.5% RHODASURFBC-720 wetting agent, and 0.57% NUOSEPT® 95 preservative. The secondslurry (“S”) had a composition of 3% RHODOLINE® 226/35 dispersant, 8%ATTAGEL® 50 suspension aid, 9% RHOPLEX® P-376 acrylic binder, 3% SILRES®M-50E silicone binder, 2.5% XLO-HVP cellulose thickening agent, 0.5%RHODASURF BC-720 wetting agent, and 0.57% NUOSEPT® 95 preservative. TheRHODOLINE® 226/35 dispersant and the RHODASURF BC-720 wetting agent werepurchased from Rhodia, the ATTAGEL® 50 suspension aid was obtained fromEngelhard Corporation, the RHOPLEX® P-376 acrylic binder was purchasedfrom Rohm & Haas Company, the DUROSET Elite 22 EVA binder was purchasedfrom National Starch and Chemical Company, the SILRES® M-50E siliconebinder was purchased from Wacker Silicones, the XLO-HVP cellulosethickening agent was purchased from Akzo-Nobel, and the NUOSEPT® 95preservative was purchased from Huls- Creanova.

As described in Example I, Ford Taurus radiator minicores were firstcoated with the two formulations, and then they were subjected toultrasonic adhesion testing after heat treatment at 150° C. for 24hours. Adhesion test results are summarized in Table G. The data showsthat even when a small amount of the RHOPLEX® P-376 acrylic binder isreplaced with a silicone binder (while maintaining the same total binderlevel in the formulation), adhesion of the catalyst coating aftertreatment at 150° C. is dramatically improved.

TABLE G Coating Adhesion and Catalytic Activity Data Ozone CoatingConversion Formulation Composition Loss (%) (%) R 3% RHODOLINE ® 47 32(NM-18688- 226/35 32-9-1) 8% ATTAGEL ® 50 6% RHOPLEX ® P-376 6% Elite 222.5% XLO-HVP 0.5% RHODASURF BC- 720 0.57% NUOSEPT ® 95 S 3% RHODOLINE ®31 28 (NM-18688- 226/35 32-10-5) 8% ATTAGEL ® 50 9% RHOPLEX ® P-376 3%SILRES ® M-50E 2.5% XLO-HVP 0.5% RHODASURF BC- 720 0.57% NUOSEPT ® 95

As described in Example I, 400 cpsi ceramic minicores were first coatedwith the two catalyst slurry formulations and then subjected tocatalytic activity testing. Ozone conversion results are summarized inTable G. The data shows that incorporation of the silicone binder intothe slurry formulation had only a minor effect on catalytic activity.

Example VIII

One catalyst slurry formulation (“T”) was prepared according to thegeneral procedure outlined in Example I. Modifications to the exactchemical composition was made as noted below. All ingredient quantitieswere based on solids relative to MnO₂. Each ingredient was addedseparately, and the slurry was subsequently mixed for 5-10 minutes on aroll mill before addition of the next ingredient. The slurry had acomposition of 3% RHODOLINE® 226/35 dispersant, 3% ATTAGEL® 50suspension aid, 10% NACRYLIC X-4280 acrylic binder, and 3% XLO-HVPcellulose thickening agent. The RHODOLINE® 226/35 dispersant waspurchased from Rhodia, the ATTAGEL® 50 was purchased from EngelhardCorporation, the NACRYLIC X-4280 acrylic binder was purchased fromNational Starch and Chemical Company, and the XLO-HVP thickening agentwas purchased from Akzo-Nobel.

Dilute solutions of the following silicone latex emulsions were preparedby mixing 1% (solids basis) of each emulsion in DI water: SILRES® M-50E(Wacker Silicones); SILRES® MP-42E (Wacker Silicones); and EL45539 VP(Wacker Silicones).

Four Ford Taurus radiator minicores were coated with the catalyst slurryformulation “T” according to the procedure outlined in Example I exceptthat drying was accomplished at 60° C. instead of 90° C. Subsequently,three of the catalyst-coated minicores were dipped in the three dilutesilicone emulsion solutions prepared above (one minicore per solution).The samples were removed from the solutions, drained, and then airknifed to remove any excess solution. The samples were dried at 60° C.for approximately 30 minutes. All four coated radiator minicores werethen heated to 150° C. for 24 hours in a forced air convection oven.After heat treatment, the samples were subjected to ultrasonic adhesiontesting as outlined in Example I. Adhesion test results are summarizedin Table H. The data shows that impregnating a MnO₂ catalyst radiatorcoating with silicone latex emulsion significantly improves adhesion ofthe catalyst coating after heat treatment at 150° C.

TABLE H Coating Adhesion and Catalytic Activity Data Silicone EmulsionCoating Loss Ozone Conversion Dip Solution (%) (%) None 64 32 1%SILRES ® M-50E 35 27 1% SILRES ® MP-42E 42 32 1% EL45539 VP 36 29

As described in Example I, four 400 cpsi ceramic minicores were coatedwith slurry formulation “T”. Subsequently, three of the catalyst-coatedminicores were dipped in the three dilute silicone emulsion solutionsprepared above (one minicore per solution). The samples were removedfrom the solution, drained, and then air knifed to remove any excesssolution. The samples were dried at 90° C. for approximately 30 minutes.The samples were then subjected to catalytic activity testing asdescribed in Example I. Ozone conversion results are summarized in TableH. The data shows that impregnation of silicone latex emulsion into aradiator MnO₂ catalyst coating has little or no effect on the catalyticactivity.

What is claimed is:
 1. A method for improving the adhesion of a firstmaterial selected from the group consisting of a catalyst compositionand an adsorption composition to a metal surface which method comprisesadding a second material selected from the group consisting ofattapulgite, montmorillonite, bentonite, beidellite, nontronite,hectorite, saponite, talc, mica, synthetic clay, silicone polymer andcombinations thereof, to said first material to form a mixture, andcoating said mixture onto said metal surface.
 2. The method of claim 1wherein said first material is a catalyst composition.
 3. The method ofclaim 2 wherein the second material is silicon polymer.
 4. The method ofclaim 2 wherein the catalyst composition comprises a manganese dioxide.5. The method of claim 4 wherein the second material is attapulgite. 6.The method of claim 4 wherein said metal surface is an atmospherecontacting aluminum motor vehicle radiator surface.